THE ECONOMY OF FOOD Digitized by tine Internet Archive in 2007 witii funding from IVIicrosoft Corporation littp://www.arcliive.org/details/economyoffoodpopOOmurrricli THE ECONOMY OF FOOD A POPULAR TREATISE ON NUTRITION, FOOD AND DIET By J. ALAN MURRAY, B.Sc NEW YORK D. APPLETON AND COMPANY 191 1 •■:.*■: :..3' PREFACE The scope of this work is fairly indicated by the Bub-title. It is described as a popular treatise because it is intended for students of domestic economy, cooks, caterers, housekeepers and managers of institutions, rather than for speciaHsts in physi- ology, chemistry and hygiene. The subject cannot be adequately treated without reference to the principles of these sciences ; but the more difficult parts have been relegated to footnotes, and the use of technical terms in the text has been avoided as far as possible. The first section deals mainly with the require- ments of the body. The origin, properties and composition of the commoner kinds of food are discussed in the second. In the third, an attempt is made to combine these two branches in a form suitable for practical everyday use — to translate protein, carbohydrates, etc., into terms of bread and meat, i.e., of breakfast, dinner and supper. 281515 vi PREFACE The interest is largely centered upon the pecuniary aspects of the subject. The prices quoted are, in most cases, those of London stores. They are, of course, Kable to fluctuation ; but they represent, as nearly as could be ascertained, the average prices prevailing in different parts of the country. All calculations in which prices are involved are explained in detail ; and the reader can therefore adjust any possible differences due to this cause. In regard to the method of estimating the relative pecimiary values of foods which the author has ventured to propound in Chapter XIV, there may be room for some difference of opinion. The object might, perhaps, have been achieved by other means ; but most of the methods hitherto adopted have proved unsatisfactory to the class of reader chiefly concerned. The calculated results given in the tables will be found easily intelligible and convenient in form. The author disclaims any special sociological skill. He does not pretend to say authoritatively what proportion of the family income either is or should be expended on food. For the purposes of Chapter XVIII, the sum of 55. per head, per week, affords an opportunity of discussing the difficulties and possibiHties of the subject, and may be regarded as a typical case. PREFACE vii With the exception of a few illustrative examples, practically all the tabular matter has been collected together in the form of an appendix to Section II. This arrangement is handy for reference, and it possesses the further advantage that the reader's attention is not distracted by masses of figures — often not wholly relevant to the issue — ^which would otherwise appear on nearly every page. As so much is founded upon data obtained by the use of calorimeters, it was deemed advisable to illustrate the apparatus, though it was impossible, within the Umits of space, to attempt any descrip- tion of their construction or the methods of using them. Standard works on dietetics, chemistry and physiology have been freely consulted, and much information has been culled from the bulletins of the Office of Experiment stations of the U.S. Depart- ment of Agriculture. The researches of Atwater and Bryant have furnished most of the data relating to the composition of foods, but some are derived from other sources. The analyses of patent and proprietary articles were supphed by the makers. For information regarding the composition of pastry, soups and other compounded foods, the author has relied chiefly upon Mrs. Beeton's cookery book. Practical men engaged in the meat, fish and grocery viii PREFACE trades have rendered valuable assistance in con- nexion with the matter relating to their several departments. The help received from Dr. T. P. Beddoes, Mr. W. R. Thomas, and Miss Elsie H. Penry in revising the proofs must also be gratefully acknowledged. Oxford, January^ 1911. TABLE OF CONTENTS PAQB Preface SECTION I. NUTRITION CHAPTER I Introductory Definition of Terms — Economy — Parsimony — Extravagance — Cheap and Dear Foods — Digestibility — Nutritive and Fattening Foods — Flesh-formers and Heat Pro- ducers — Popular Fallacies — Errors in Diet . , I CHAPTER II Physiology of Ntjtrition Anatomical Composition of the Body — Proportion of Parts — Respiration — Digestion — Ferments — Saliva — Pepsin — Bile — Pancreatic Juice — Chyme — Absorption — Lymph — Excretion — Mastication — Inhibition — Preservatives in Foods — Percentage Digestibility — Time occupied in Gastric Digestion — Constituents of Urine 13 CHAPTER III Chemistry of Nutrition Chemical Composition of the Body — Nature of Food — Protein — Fat — Carbohydrates — Metabolism — Heat o£ Combustion — Physiological Values — Nutritive Value of Gtelatin and Amides , . . . , .25 CHAPTER IV Quantity of Food Methods of Investigation — Estimation of Urea and Car- bonic Acid — Results of Experiments — ^Voit and Petten- kofer — Minimum of Protein — Chittenden's Views — Non-nitrogenous Nutrients — Standard Diet — Size of Individual — Climate and Exposure — ^Work — Liebig's Views — Value of Additional Protein — Diet for Work — Various Authorities — Increase and Reduction of Weight — Pregnancy and Lactation — Diet for Children. . 39 ix X TABLE OF COISTTENTS PAQB SECTION II. FOOD CHAPTER V CLASSinCATION AND GENERAIi PROPERTIES OP FoODS. Classification of Foods — Nutritive Character — Nutritive Ratio — Non-nutrient and Refuse Parts — General Pro- perties of Animal and Vegetable Products . . 64 CHAPTER VI Butcher's Meat Beef — Veal — Mutton — Lamb — Pork — Bacon — Seasons — Methods of Cutting Up — Sides — Fore and Hind Quar- ters — Principal Joints — Average Weight and Price of each — Proportions of Bone — Fat and Lean — Com- parison of Different Kinds of Meat — Sundries . . 69 CHAPTER VII Poultry, Game and Fish Fowls — Chickens — Ducks — Geese — Turkeys — Rabbits — Fresh Fish— Cured Fish— Methods of Curing— Shell Fish — Seasons — Average Size and Prices — Propor- tions of Refuse and Edible Matter . . . .85 CHAPTER VIII Dairy Produce Cow's Milk — Composition — Goat's Milk — Mother's Milk — Preparation of Bottle Milk for Infants — Humanized Milk — Preservatives — Sterilized Milk — Skim and Separated Milk — Cream — Butter — Margarine — Cheese — Whey — Eggs — Composition — Average Size and Price of Eggs — Testing and Preservation of Eggs . . 92 CHAPTER IX Cereajls, Farinaceous Products, etc. Characteristic Properties — Wheat — Flour — Bread — Macar- oni — Vermicelh — Semolina — Barley — Rice — Oats — Oatmeal — Crushed Oats — Maize — Hominy — Cornflour — Arrowroot — Tapioca — Sago — Pulse — Beans — Peas — Lentils — Nuts — Sugar — Treacle and Golden Syrup — Vegetable Oils — Vegetable Margarine . . 103 TABLE OF CONTENTS xi PAGE CHAPTER X Fbuits and Vegetables Fresh Vegetables — Composition — Nutritive Value — Hygienic Properties — Fruit — Composition — Ripe and Unripe Condition — Jam — Failure to Jelly — Honey — Dried Fruit 116 CHAPTER XI Prepared Foods, Packet Goods, Patent and Proprietary Articles Packet Goods — Infants' and Invalids' Foods — Cereal Preparations — Milk Foods — Mixed Foods — Malted and Peptonized Products — Meat Juices and Extracts — Commercial Peptones — Meat Powders and Pastes — Gelatin — Table Jellies — Desiccated Eggs — Egg and Custard Powders . . . . . . .121 CHAPTER XII Spices, Condiments and Miscellaneous Articles Spices, Aromatic Properties — Pungency — Adulteration — Nutmegs — Mace — Pimento — Cloves — Cinnamon — Cassia — Ginger — Essences — Vanilla — Almonds — Lemon — Condiments — Salt — Pepper — Cayenne — Mustard — Vinegar — Saccharin — Yeast — Baking Powders — Rennet . . . . . . .131 CHAPTER XIII Effects of Cooking Food Methods of Cooking — Wet and Dry Heat — Objects of Cooking — ^Various Effects — Sterilization — Influence on Digestibility — Coagulation — Loss of Weight — Loss of Nutrients — Boiling Meat — Roasting Meat — Boiling Vegetables — Steaming . . . . . .143 CHAPTER XIV The Relative Value of Foods Relation of Prices to Nutritive Values of Foods — Questions of Pecuniary Economy — Values of Several Constituents — Determination of Values — Definition of Relative Value — Application of Formula — Comparison of Rela- tive Values with Market Prices . . . .149 xu TABLE OF CONTENTS PAGE CHAPTER XV An Appendix to Section II showing the Composition and Relative Values of Foods Explanation of Tables — A. Animal Products — B. Vegetable Products — C. Cereal and Milk Preparations — D. Meat Preparations — E. Milk Preparations and Miscellaneous Products — F. Relative Values of Foods — G. Per- centages = ounces per lb. . . . . .160 SECTION III. DIET CHAPTER XVI Computation of Diets Adaptation of Foods to Requirements — Adjustment of Quantities — Difficulties — Case of Two Foods — Pro- portions required to Produce a given N. ratio — Arithmetical Method — Graphic Solution — Quantities to Produce Specified Diet — Simultaneous Equations — More than Two Foods — Indefinite Number of Solutions — Maximum and Minimum Quantities . . . 183 CHAPTER XVII National Diets Staple Foods in Various Countries — Use of Animal Foods in Cold Climates — Eskimos — Importance of Variety — Theoretical Maximum of any Food — Bread — Bread and Butter — Oatmeal — Potatoes — Meat — Mixed Diet — Quantities Required — Relative Cost . . .196 CHAPTER XVIII Familiar, Diet Ways and Means — Requirements of Families — Proportion of Income Available for Food — Typical Case — Maxi- mum Amount of Meat — A Day's Rations — Three Meals — Possible Variations — Fruit and Vegetables — Milk Puddings — Batter Puddings — Boiled Pastry — Bread Puddings — Soups — Stock — Milk Soup — Clear Soups — Vegetable Soups — Thick Soups — Variation of Morning and Evening Meals ...... 206 CHAPTER XIX Special Diet Invalids — Dietetic Treatment — Constipation — Dyspepsia — Obesity — Banting — Diabetes — Rheumatism and Gout — Vegetarian Diet ....... 235 SECTION I. NUTRITION CHAPTER I INTEODUCTORY Economics, so far as they regard only inanimate things, serve only the low purposes of gain ; but where they regard human beings they rise higher. Plutarch. A GOOD deal of confusion exists regarding the mean- ing of the term economy. In the ordinary lan- guage of the housekeeper it is associated with the idea of frugality, thrift or saving. Ruskin has pointed out that " economy is not saving any more than it is spending.'* It is obvious, however, that it does, or may, mean saving if one chooses that it shall do so. The word is also used in a different sense. It is derived from the Greek otVo?, a house, and vofio^, to manage or control. That, no doubt, is what it originally implied, and the expression " domestic economy " is, therefore, redimdant. But the mean- ing was gradually extended to the administration of the resources and concerns of any community or establishment, and ultimately to the organiza- tion of any complex unity. Thus we speak of animal and vegetable economy, the economy of nature, and so on. 2- \ : >' I >: • - - BdONOMy. OF FOOD * It is in this latter sense that the term economy has been introduced into the title of this book, which treats of the nature, sources, composition and functions of various kinds of food. As, how- ever, it is intended to deal with the subject largely from the former point of view, i.e. with reference to the cost and thrifty use of food, the very am- biguity of the term renders it a peculiarly appro- priate one for the purpose. In the sense of saving, economy is often con- founded with parsimony ; but they are not the same. Saving is not economy if it interferes with the purpose in view. The purpose of taking food is to satisfy the cravings of hunger, to provide for the requirements of the body, and, to a certain extent, to gratify the legitimate sensations of the palate. Fifty per cent, of the food might be saved by going on haK rations ; but if hunger were not appeased, this could not properly be called economy, except under famine conditions. Potatoes are cheaper than meat, and hunger may be appeased by the former at less cost than by the latter ; but if the body be not properly nourished, there would be no true economy ; the saving would be, in effect, not gain but loss. Gratification of the palate is, perhaps, a matter of secondary, but still of considerable, importance, especially for those engaged in sedentary occupa- tions. Nervous exhaustion is frequently accom- panied by loss of appetite, and in such a condition a person may not eat enough to sustain him pro- perly if the food be not to his taste. It is not econ- omy, therefore, but^^the reverse to provide food — however cheap — ^which the person for whom it is intended can't or won't eat. Even minor prefer- INTRODUCTORY 3 ences should be considered as far as possible. Con- diments and flavouring materials, though of no value in themselves, may prove useful in this connexion. Any saving in cost may be regarded as economy, in the pecuniary sense, provided the food is of a kind suitable for the nourishment of the body, sufficient in quantity, and sufficiently attractive to be eaten with a relish. Any expenditure be- yond the minimum required to obtain such food may be, by contrast, regarded as extravagance. It is beside the question to argue that the more expensive food might be nicer, and that, if the person could afford it, such extravagance would be justifiable. At present, the object is merely to arrive at an understanding regarding the meaning of the terms employed. The kind and quantity of food that should be eaten are indicated, to some extent, by instinct — the sensations of the stomach, the palate and the nostrils ; but luider the conditions of civilized life, this is not a sufficient or altogether reliable guide. A person might habitually over-eat and yet be in a state bordering upon starvation. Cases of this kind are probably of rare occurrence, but they are conceivable. They are more likely to arise in con- nexion with the feeding of children than of adults. If the food be unsuitable, either in quantity or quality, some portion of it will be wasted, and health and comfort will be more or less deranged. Profound ignorance concerning the requirements of the body and of the properties and functions of the various kinds of food is very prevalent, even amongst the educated classes. The majority of people are content to be guided in their choice of 4 ECONOMY OF FOOD food, by what is customary in the class and coun- try to which they belong. Many of the well estab- lished dietetic customs are based on experience, traditional and personal, and they are usually, but not invariably, sound and satisfactory in the main. But they are subject to modification in detail, and owing to the general lack of knowledge, errors in diet are far from uncommon. Stunted growth and retarded development in children, and various dis- orders in adults, may often be traced to this cause. Waste of resources is another consequence, and, for the poorer classes at least, a very serious one. The effects of an occasional indiscretion may be almost imperceptible if the normal diet of the indi- vidual be well adapted to his requirements ; it is the systematic error that it is important to guard against. The vague and indefinite phraseology used in describing foods is, no doubt, responsible for the inaccuracy of many of the popular notions. *' Rich," " strong " and similar expressions are used in different, sometimes in contradictory, senses, and not infrequently without any definite meaning at all. Terms such as nutritious, fatten- ing, digestible, are imperfectly understood. Cost and value are often confused. The confusion of ideas is particularly striking in connexion with the use of the word nutritious. Synonyms might easily be found for it, but it is by no means easy to define it. All foods are nutritious — otherwise they could not properly be called foods. When one food contains a larger proportion of nutritive substances than another, it is commonly said to be more nutritious ; but it would be more accurate to say, simply, that it is more ccncen- INTRODUCTORY 6 trated. A pound of bread contains, roughly, about four times as much nourishment as a pound of pota- toes, and may, therefore, be said to be more nutri- tious. But, on this hypothesis, a pound of bread is not more nutritious than four pounds of potatoes. Highly concentrated foods have their special uses ; so also have those of more bulky character. The concentration of the foods is perhaps more important when they are considered with reference to their cost than in any other connexion. A larger or smaller proportion of the nutritive matters of foods is usually present in such a con- dition that it cannot be assimilated and is, there- fore, said to be indigestible.^ No nourishment can be derived from this material ; it simply passes through the intestines and is excreted unchanged. Two foods which contain the same proportions of nutritive matter will not, therefore, be equally nutritious unless they are equally digestible. For example, suppose the digestibility of an egg to be affected — adversely or otherwise — by cooking, the egg would be rendered less, or more, nutritious accordingly, though the amount of nutrients re- mained the same. The nature of the nutrients must also be taken into consideration. For present purposes, they may be roughly divided into two classes, viz. nitro- genous and non-nitrogenous. They are some- times referred to as flesh-formers and heat-producers, respectively. This distinction was introduced some years ago in order to avoid the use of scien- tific terms ; but it is radically unsound and has ^ The term digestibility is also used with reference to the length of time the food remains in the stomach. (See p. 22.) 6 ; ECONOMY OF FOOD proved misleading. The " flesh-formers " produce more heat than some of the so-called " heat-pro- ducers '* ; and the latter are intimately connected with the phenomena of tissue formation. It is true, however, that they have different functions, and there can be no true comparison between foods in which the relative proportions of these ingredients vary widely. The foods in which nitrogenous nutrients pre- dominate — chiefly those of animal origin — are generally the more expensive ; and this appears to have given rise to a widespread belief that these foods are the more nutritious. It may be true that many people would do better if the proportion of nitrogenous nutrients in their food were increased. It is true that, within certain limits, an excess of these constituents is harmless, and that a deficiency is fatal ; but the generalization above referred to is, to say the least, extremely rash. It is also com- monly held that the non-nitrogenous nutrients — especially starch and sugar — are essentially and intrinsically fattening. It is not a little curious that these two opinions should be frequently enter- tained by the same persons, for the one is a manifest contradiction of the other. Neither nutrition nor fattening is attributable to any single constituent of the food ; they depend largely upon the proportions of the two classes of nutrients. The proportions required vary accord- ing to the circumstances ; but when — and only when — ^all the other requirements of the body have been satisfied, the excess of either kind may be stored up as fat. Persons who for any reason desire to reduce their weight — chiefly athletes in training and those INTRODUCTORY 7 who have a disposition towards obesity — ^are fre- quently quite eccentric about their diet ; they shun potatoes and certain other kinds of food, take all their bread toasted, eat raw or only partially cooked meat, and so on. In some cases the systems adopted involve considerable self-denial for which there is no necessity. The purpose could usually be accomplished equally well on a rational ordinary diet if properly regulated. Comparisons of one food with another are apt to be misleading unless all the circumstances are taken into account. It may be said, however, that, whereas bread contains four or five times as much nutritive matter as an equal weight of potatoes and is not less digestible, it is difficult to see what advantage is gained by substituting the former for the latter in the diet of a person who wishes to reduce weight. Bread may possibly be rendered more — or less — digestible by toasting, but the amount of nutritive matter in it is not perceptibly altered. As, how- ever, a certain amount of moisture escapes in the process, what is left — the toast — is more concen- trated than the fresh bread. Possibly some people may find toast less fattening because they eat less of it. In that case, of course, it is merely a question of the quantity and not of the condition of the bread. It is a mistake to suppose that raw, or semi-raw, meat is more nutritious than that which has been moderately cooked. The latter is more easily masticated, and probably on that account more readily digestible ; ^ and as it is drier it contains ^ The contrary has been maintained but the evidence on this subject is not very satisfactory. j 8 ECONOMY OF FOOD actually a larger proportion of nutritive matter than the same meat in the raw condition. In this case also, the quantity eaten must be taken into account. A certain amount of loss is incidental to nearly all processes of cooking (see p. 144), but if the cooking be not overdone, the loss is not, as a rule, very great. When meat is over-cooked it is probably rendered less digestible than that which is underdone, and the incidental loss is much greater. The notion that raw meat is the more nutritious may be attributable to this fact. Soups and meat extracts are popularly supposed to be very nourishing, and are frequently admin- istered to invalids on that account. The term *' essence of beef " and similar expressions found in the advertisements of commercial preparations of this kind, are probably intended to encourage this idea. But if it be true, as indicated above, that the loss of nourishing matter, resulting from the moderate cooking (boiling) of meat, is not very great, it follows that there cannot be much in the broth so prepared. If the meat be " boiled to rags " the loss will be considerable, but the amount of nutrients in the soup will not be correspondingly large. Much of the substance extracted from meat by boiling or stewing undergoes a partial decom- position whereby its nourishing properties are greatly reduced. The products, however, impart an agree- able, appetizing flavour and odour to the broth, and they have a marked stimulating effect which may be highly beneficial to invalids or to persons suffering from bodily or nervous exhaustion. Soups which have been thickened by the admixture of considerable quantities of flour, barley, fresh veget- ables, etc., are, of course, an entirely different INTRODUCTORY d case. Each of these foods possesses a definite nutritive value of its own ; but this value is not altered — ^neither increased nor diminished — by- mixing the foods with the " stock '' or soup proper. With very few exceptions, foods do not react upon or affect each other in any way ; they do not, therefore, become more nutritious when mixed together. It is highly advantageous to partake of certain different kinds of foods, e.g. meat and potatoes, in conjunction ; but nothing is gained by actually mixing them. The nutritive value of, say an egg and milk, or bread and milk, is no greater than that of the same two foods taken separately at, or about, the same time. On the other hand, some foods are rendered much more palatable or agreeable by mixing. Half the art of cookery consists in the concoction of such judicious mix- tures ; and, since the nutritive value of the foods is not affected, there is no reason why taste should not be gratified in this way. The nutritive value of certain foods has sometimes been attributed to wrong causes, and in other cases it has been greatly exaggerated. Milk and eggs are cases in point. Milk is a very useful and valuable food. It is pre-eminently suitable for young children and invalids. It has been called a perfect food. This, however, is an exaggeration except in its appli- cation to infants. For adults, there is no perfect food ; their requirements vary, but they are not the same as those of children. Milk is recommended for invalids, not because it contains a large pro- portion of nutritive matter, but largely for the contrary reason, i.e. because it is not too concen- trated ; even so, it is often necessary to dilute it. 10 ECONOMY OF FOOD The nutritive matter in milk is present in smaller proportion than in many other foods ; but it is present in such a condition that it is very easily assimilated. It is chiefly to this fact that milk owes both its special and its general utility. The statement that skim milk and butter milk are more nutritious than fresh whole milk can scarcely be called a popular fallacy, as it is not generally accepted, though often repeated. At any rate, it is absurd. It probably originated with some one obsessed with a morbid love of paradox. The amount of nourishment in a food cannot be increased by abstracting a portion of it. Eggs are commonly regarded as a highly nutri- tious food, but they are somewhat sparingly used " because they are so dear.'' But if eggs contain more nourishment than other foods, they may be actually cheaper, even at a relatively higher price. As a matter of fact, eggs do not contain so large a proportion of nourishment as is sometimes sup- posed ; and compared with many other foods, they are dear. That is to say, that the same amount of nourishment could be obtained from other foods at less cost. In the celebrated system of Banting, great atten- tion was paid to the quantity of liquids consumed ; and many people entertain the ridiculous notion that water itseK is fattening. In Banting's case the restriction referred chiefly to the use of alcoholic beverages which, when taken in large quantities, have a tendency to increase weight. This effect, however, is due, not to the water, but to the solids, of which malt liquors and certain wines contain a considerable proportion. In the treatment of obes- ity, restriction of the quantity of water frequently INTRODUCTORY 11 leads to a reduction of weight ; but it has been shown that this result is due simply to reduction of the quantity of water in the body, and that the quan- tity of fat is scarcely affected one way or the other. It may be questioned whether it is wise to effect a reduction of weight in this way. If less than a certain minimum quantity of water be consumed daily, health and comfort will suffer. Medical men consider that many people — especially women — do not drink enough. A very large excess of water may also prove injurious ; but considerably more than is actually necessary may be taken without any perceptible effect whatever. Any normal healthy individual may safely drink as much water as he feels inclined to. Another notion, which still lingers, is that " fish is good for the brain because it contains a large proportion of phosphorus." It is probably true that fish is good for the brain, not for the reason alleged, but because, being readily digestible, it is good for the stomach. Many brain workers prefer fish to meat for luncheon on this account. The theory of Buclmer,^ Ohne Phosphor Jcein Gedenkey on which the notion is apparently founded, is not supported by reliable evidence, and is now dis- credited. There is no reason to believe that the proportion of phosphorus in other foods is insuffi- cient for the nourishment of the brain as well as other parts of the body. Some foods, e.g. eggs, contain a larger proportion of phosphorus than fish does. The shimmering or so-called phosphores- cent appearance that fish exhibits in the dark is no evidence of the presence of phosphorus — ^a substance 1 Kraft und Stoff. 12 ECONOMY OF FOOD which in that condition is intensely poisonous. The phosphorescent appearance is due to the action of certain bacteria, and is a sign of incipient decom- position. The Hst of popular fallacies concerning food might be extended indefinitely ; but they cannot be properly discussed at this stage, and nothing is gained by multiplying the instances of erroneous ideas. The only effective way of dealing with them is by systematic statement of the truth so far as it is known. CHAPTER 11 THE PHYSIOLOGY OF NUTRITION It is certain that the bodies of all animals are in a constant flux, from that never ceasing attrition which there is in every part of them. Butler's Analogy. It is common knowledge that the body is made up mainly of the skeleton, flesh, organs or viscera, and the blood and nervous systems. The heart and lungs are situated in the chest or thorax, and are commonly referred to as the thoracic viscera. The remainder, consisting chiefly of the alimentary canal, i.e. the stomach, gut or intestines, and the glands connected with the same, are situ- ated in the belly or abdomen, and are collectively known as the abdominal viscera. The relative proportions in which these various parts contribute to the mass of the body are esti- mated to be, on the average, as follows : — Estimated Avebaqb Pboportion of Parts in the Body. Per cent. Flesh (including fat and skin) . . .66 Skeleton 16 Viscera (thoracic and abdominal) . . 9 Blood 7 Brain and nerves ..... 2 100 18 14 ECONOMY OF FOOD By multiplying each of these items by | we should obtain approximately the actual weight of each, in a person of 150 lbs. weight, which is about the average weight of a full grown man. The lungs are chiefly concerned with respiration. The air, which is inhaled by their action, is absorbed by the blood and so carried to all parts of the system. In this way all the tissues are subjected to a con- tinuous process of gentle oxidation, which is the very essence of life and which has several conse- quences, highly important from a dietetic point of view. The oxidation which takes place in animal bodies may be compared to a smouldering fire. It is actually and in truth, a process of slow combustion. The warmth or heat of the body is produced by it. The substance is gradually consumed, and fresh fuel, i.e. food, must be constantly supplied in order to maintain it. If fuel be added to a smouldering heap more quickly than it is consumed, the mass will be increased. If it be not added so quickly, the mass will be gradually diminished and in time combus- tion will cease. But if fuel be added to the heap at exactly the same rate as it is consumed, the mass will remain practically constant. The nourishment of animal bodies by food is an exactly parallel case. If the quantity of food be not sufficient to counterbalance the loss of substance due to oxidation, the body loses weight, and will ultimately die of starvation. On the other hand, if more material be absorbed than is lost by oxida- tion in the same time, the excess can be stored up, and increase of weight results. The normal case is that in which the quantity of food absorbed into THE PHYSIOLOGY OF NUTRITION 15 the system is just sufficient to make good the loss, and neither gain nor loss of weight occurs. The food by which the body is nourished under- goes many transformations. It is first digested, then absorbed and distributed to all parts of the system. The process of di- gestion is performed by various fluids called digestive juices, to the action of which the food is successively exposed. The digestive juices contain certain pecu- liar products, called enzemes or unorgan- ized ferments, which act upon the various constituents of the food and cause them to undergo the changes about to be described. Digestion begins in the mouth. In the process of masti- cation the food be- comes mixed with saliva. This fluid contains a ferment which acts upon the starchy matter of ^^^- ^• hrf^a c\ n n rl f a rin o no Alimentary canal, showing tlie mouth (M) ; Uieau ana larmace- gullet(G); stomach (5); duodenum (D); OUS foods, and con- '"'^^^^''^''^'and^rVctum (i^'*^^^ 16 ECONOMY OF FOOD verts it into a soluble sugar-like compound which is afterwards easily absorbed. In the stomach, the food is acted on by the gastric juice. This is of quite a different character from saliva. It is slightly acid, and contains a ferment called pepsin, which acts on the albuminoid or protein compounds such as the lean of meat. The latter are thereby converted into soluble forms called peptones, and are, therefore, said to be peptonized. The partially digested food passes from the stomach into the intestine which also receives the secretions from two large and important glands called, respectively, the liver and the pancreas. The secretion from the liver is called bile ; it is chiefly concerned with the digestion of fats. The latter do not entirely lose the fatty character, but become emulsified, i.e. broken up into extremely minute particles of a semi-liquid character, which remain diffused through the fluid in which they are suspended. This condition, it will be seen, some- what resembles that of the cream in fresh milk. The pancreatic juice, though it differs from both the saliva and the gastric juice, possesses peculiar properties which enable it to perform, to some extent, the functions of both. It acts upon starchy mat- ters which have escaped the action of the saliva, and also upon protein compoimds which have not been completely digested in the stomach. These effects are due to the action of ferments similar to those previously referred to. As digestion proceeds, the food is reduced first to a sloppy condition and finally to a liquid state. This fluid is of a milky consistency, and is called chyme. As it passes downwards, it is absorbed by THE PHYSIOLOGY OF NUTRITION 17 hair-like processes, called villi, which project from the walls of the intestiae. Within the walls of this tube, the constituents of the food which has been absorbed undergo fur- ther changes, and soon pass into the blood vessels with which the intestine is abundantly supplied. The smaller vessels unite to form the larger ones by which the blood is distributed to all parts of the body. The system is much too complex to be described here. Suffice it to say that the larger vessels branch in various directions, and branch again, gradually diminishing in size, and end finally in a close meshwork of fine capillaries in intimate contact with the tissues with which they are associ- ated. The walls of these capillary vessels are very thin, and some of the blood plasma exudes through them. This fluid is called the lymph. It fills up all the spaces between the cells and thoroughly bathes the tissues, which are nourished and restored by it. It is in this way that the waste due to oxidation is repaired. The lymph is then drained ojff by a special set of vessels called the lymphatics, and is ultimately returned to the blood to be reoxidized in the lungs, and fortified again by additions from the intestines. It will be seen that digestion consists essentially in the reduction of solid foods to the liquid state, in which alone they can be absorbed and pass into the system. Surplus and indigestible portions of the food, i.e. any solid matter which has not been dissolved, or otherwise rendered fluid, by the action of the digestive juices, together with any excess of the latter, effete membranes, etc., pass right through the intestine and are excreted as faeces. 18 ECONOMY OF FOOD The term digestibility refers to the rapidity and thoroughness with which food is transformed into chyme. Obviously, it depends partly on the indivi- dual and partly on the food. If one of two different foods, or portions, of food undergo this transforma- tion more rapidly or more thoroughly than the other in a given, normal individual, it is said to be more digestible. The digestibility of any food depends upon a number of circumstances of which the following are the more important : — 1. The Extent of Surface. The greater the extent of surface exposed to the action of the digestive juices the more rapidly will the process be accomplished. The extent of surface is greatly increased by pulverizing and disintegrat- ing the food before it is swallowed. This is generally effected by chewing, and it is one of the ends to be served by thorough mastication. Food swallowed in lumps is not so much exposed to the action of the ferments, and it may be excreted practically un- changed. In that case comparatively little nour- ishment will be derived from it ; if not discharged, it tends to block the passage and hinders the other processes. Tough meats should, therefore, be minced ; if very hard, they should be reduced to the condition of potted or sausage meat. This not only makes them more readily digestible, but it has the further advantage that it affords an opportunity of ^making them^more appetizing by mixing, spicing and garnishing in various ways. Some of the cheaper meats, e.g., Hghts, hearts, etc., which are so hard or tasteless as to be practically imeatable, can be profitably used when so treated, THE PHYSIOLOGY OF NUTRITION 19 The flesh of nimble and active creatures, such as deer, goats and wild birds, is generally tougher than that of the more sedentary sheep, oxen and barn- yard fowls. Newly killed meat, too, is tougher than that which has been " hung " for a few days, because the rigor mortis — the rigidity of the body which sets in shortly after death — ^gradually passes away. Fowls and other small animals, which can be killed on the premises, may sometimes be cooked before rigor mortis sets in, and may thus be obtained in a tender condition in warm weather without risk of decomposition. In the case of butcher's meat, this is not usually convenient. The tissues both of animals and vegetables be- come tougher as they get older. In vegetables — • and especially in green vegetables — the proportion of woody fibre increases very rapidly after a certain stage. This material is difficult to masticate, is very resistant to the action of the digestive juices, and apt to produce flatulence. Cereals, e.g. wheat and oats, are generally either crushed or gromid, and, it appears, the more finely they are ground the better. Green vegetables, such as cabbage, are sometimes " mashed," but if they have already got to the tough stage, they will not be much improved thereby, as the process of mashing has very little effect upon the fibre. The admixture of butter or other fat with mashed potatoes has an adverse effect on the digestibility ; the fat tends to protect the constituents from the action of the aqueous digestive juices, and it causes the substance to cohere in such a way that it may be swallowed in clots unmixed with saliva. Quite a different effect is produced by crushing potatoes in a perforated presser ; by this means any hard lumps are re- 20 ECONOMY OF FOOD duced or eliminated, the extent of surface is greatly increased, and the substance is rendered more digestible. 2. The Activity of the Digestive Juices. Many substances retard or inhibit the action of ferments. They are called antiseptics. Some of them, e.g. formalin, borax, salicylic acid, common salt, etc., are used as preservatives for food. If they do preserve the food from the action of fer- ments, they must render it less digestible. In some respects digestion closely resembles the initial stages of decay. A certain amount of salt is necessary, but excess is probably injurious, for the reasons given above. Much of the salt or other substances used to preserve bacon, fish, etc., can be extracted with water before cooking, and the digesti- bility of the food is thereby increased. The ferments act best at, or about, the tempera- ture of the body, and very hot liquids, e.g. tea, soup, or cold substances, such as iced foods or water, tend to retard their action. If these substances are slowly sipped, they will be comparatively innoxious, as they will be cooled, or warmed, before reaching the stomach, and can only affect the saliva ; but if they are taken in gulps along with food, the tempera- ture effects may be considerable. Cold liquids have also a tendency to consolidate fats and so reduce digestibility. 3. A Suitable Proportion of Water. A certain amount of water is required to form the juices, and to dissolve and carry off the products resulting from their action. Insufficiency of water, therefore, tends to retard digestion. Highly con- THE PHYSIOLOGY OF NUTRITION 21 centra ted foods like cereals, etc., require to be cooked with a large quantity of water. Some persons can take oatmeal porridge only if it is " made very thin," others cannot take it unless it is diluted to the condition of gruel. Dried meats, fish and fruits, are less digestible than the same foods in a fresh condition ; this has been attributed to deficiency of water, but it may be due, in part, also, to other causes. Excess of water taken along with food, by unduly diluting the juices, also renders them less effective and retards digestion. In general, the constituents of animal foods are more completely digested than those of vegetables ; Digestibility of Foods (Atwateb). {Proportions digested). Percentages Digested. Percentages Digested. Aniina.1 1 Vegetable 1 Foods. Foods. Pro- Fat. Carbo- Pro- Fat. Carbo- tein. hydrates i tein. hydrates P. ct. P.ct. P. ct. i [ P.ct. P.ct. P.ct. Beef . . 100 95 ; Wlieat flour Veal . . 100 95 — (fine) . 85 id r—i Mutton 100 95 — Do. 03 d Pork . . 100 95 — (medium) 81 & a Fish and Do. TJ t3 Oysters 100 95 — (coarse) 75 Milk . . 100 96 100 Rice . 85 § Cheese 100 95 100 Macaroni . 85 1 i Butter — 96 — Rye flour . 78 Margarine — 95 — Maize-meal 85 1 i Tallow — 95 — Potatoes . 75 s Lard . . — 95 — Cabbage . 80 §3 ^ Oils . . — 95 — Turnips . 80 ft ft Eggs . . 100 98 Peas . . Beans 85 85 o 00 § 22 ECONOMY OF FOOD the latter are often so enclosed in the cellular and fibrous tissues with which they are associated that they are protected from the action of the digestive juices. A certain proportion of the nutrients in vegetable foods is therefore usually excreted un- changed in the faeces. Within limits, digestibility is not affected by the amount of the food, bodily work, age or other acci- dental circumstances, and it does not vary greatly in different individuals in normal health. In popular language, the term digestion is gener- ally used exclusively with reference to the processes which take place in the stomach. In this respect, the differences between individuals are more con- siderable. Weak or slow gastric digestion arises from immobility of the organ, or from defective secretion of ferments. Too rapid secretion of gastric juice causes dyspepsia. Persons who suffer from these disorders are not, however, necessarily or usually deficient in absorptive capacity. Under like conditions, the time occupied in gastric digestion of any given food probably does not vary much in normal healthy individuals. But con- siderable differences have been observed in the digestibihty of different kinds of food. Some remain much longer in the stomach than others ; but there is no reason why these should be avoided by healthy people, as they are ultimately trans- formed into chyme without discomfort or incon- venience. Observations upon the length of time that various foods remain in the stomach are probably reliable so far as they go. They are, however, of very little real value because, apart from the differences in individuals, the time depends upon the quantity of THE PHYSIOLOGY OF NUTRITION 23 food, what it is associated with, how it has been prepared and cooked, degree of mastication and so on. It is said that beef leaves the stomach in less time than pork, but it is probable that, ceteris 'paribus, a tough sample of beef will require more time than one of tender pork. Also the digesti- bility of the various joints of each are not alike. Some of the results obtained are given in the follow- ing table, but they must be accepted with con- siderable reserve. * Digestibility of Foods. ' (Length of time food remains in stomach.) Animal Foods. Vegetable Foods. Beef, raw . 2 hours Bread 2 J hours „ boiled . 3 > Potatoes . 2-2i „ „ roasted. 4 > Rice . H » Eggs, raw. . . 2i » Lentils . 4 „ soft boiled . n » Peas . 4i „ „ hard boiled 3 > Apple, raw . 3i „ Fresh fish. . . 2* » Cabbage . 3 Salt fish . . . 4 > Cauliflower . 2i „ * Hutchiaon. When ordinary fuel is burned in a fire, the prin- cipal products of the change are carbonic acid gas and water. The same substances are also produced by the oxidation that takes place m animal bodies, and they are given off from the lungs in respiration. There is, however, one respect in which the analogy does not hold, and it is of con- siderable importance. When nitrogenous com- pounds are consumed by fire, the nitrogen is liberated 24 ECONOMY OF FOOD in the free state, and escapes with the other products (carbonic acid, etc.) ; but when the nitrogenous compounds, ot wliich animal bodies are largely composed, are oxidized in the normal course of respiration, the change takes place at a much lower temperature, and the nitrogen appears in the form of a compound called urea. This substance is non- volatile ; it does not, therefore, escape with the other gases from the lungs, but passes into solution in the blood, whence it is eUminated by the kidneys, and is discharged in the urine. ^ Excess of salt and certain other useless or effete matters are also eliminated from the blood and discharged in the same way ; the latter are, how- ever, of minor importance from the present poiat of view. CHAPTER III THE CHEMISTRY OF NUTRITION Der Mensch ist was er isst. Feuerbach. A VERY large number of chemical compounds enter into the chemical composition of the animal body. For present purposes they may all be grouped under the following heads — ^albuminoids or proteids, fats, water and the so-called mineral or earthy substances. The relative proportions in which these various constituents are present vary according to circumstances. In a healthy adult man, the average may be approximately as follows : — Per cent. Per cent. (Dry). Water Fat Albuminoids Mineral matter 64 18 14 4 11 100 100 The red flesh or muscular tissue, skin, nerves, vessels and various organs-— heart, stomach, liver, 26 26 ECONOMY OF FOOD etc. — all consist mainly of albuminoid compomids mixed or associated with a large proportion — 70 to 80 per cent. — of water. The substance of hair, cartilage (nails, etc.) is of a similar nature, and even bones contain a large proportion of the same material. Fat is found in largest quantity in the region of the kidneys which it surrounds and encloses ; but it also occurs in masses or layers in various other parts of the body. Fat enters into the composition of bones, and it is usually associated also with the muscular and other tissues in larger or smaller quantities. Beefsteak, free from all visible fat, contains from 1 to 3 per cent, of that ingredient. The earthy or mineral matter consists mainly of phosphate of lime. It occurs chiefly in the bones, and it is to the presence of this constituent that bones owe their hardness and rigidity. The pro- portion increases with advancing age, and the bones gradually become harder and more brittle. Phosphate of lime, as the name implies, is a compound ^ of Hme and phosphoric acid. It may be formed by the action of lime on other phosphates, e.g. phosphate of potash. Phosphates are essential constituents of plants, and are, therefore, present in nearly all vegetable as well as animal foods. The phosphate of hme found in the bones is derived from this source. Water is a compound of two chemical elements called hydrogen and oxygen, respectively. It is produced when hydrogen, or compounds of hydro- gen, are burned or otherwise oxidized. Being, itself, a product of oxidation, water does not bum, ^ The composition is shown by the chemical formula [CaCPaOg or C8i^{V0^)i. THE CHEMISTRY OF NUTRITION 27 i.e. it cannot be further oxidized. It is of necessity well known to every one, and it is unnecessary to enter into any further description of its properties. It has been shown above, that about 90 per cent, of the dry matter of human bodies consists of com- pounds classed as albuminoids and fats. Both suffer continual loss by oxidation, and the need of food arises chiefly from the necessity of constantly replacing them. It is obvious, therefore, that only substances which contain these compounds, or constituents capable of being changed into them by the physiological processes to which they are subject, will be suitable for use as food. Meat, bread, vegetables and other foods contain albuminoids and fats, and some of them a number of compounds which belong to a different class called carbohydrates. Experience shows that the last-mentioned may be used to satisfy hunger, and that they also have nutrient properties. In order to explain this, it is necessary to refer to the composition and properties of these different classes of compounds, and show their relations, one to another. They are all complex substances, and the complete investigation ranges into the most difficult branches of organic chemistry. All that is necessary for present purposes, however, is tolerably well known, and is not difficult to follow. The group of albuminoids or proteids, as they are indifferently ^ called, comprises a large number of compounds. Some of these, e.g. white of egg, milk curd, blood clots, lean meat, etc., are externally ^ The terms albuminoids and proteids are used by some authors in different senses, and from a purely chemical standpoint it is sometimes advantageous to do so, but for present purposes it is unnecessary to make any distinction. 28 ECONOMY OF FOOD very different ; but they all resemble each other very closely in chemical composition ; and they exhibit characteristic properties which show that they belong to the same class. They are composed of the elements, carbon, hydrogen, oxygen, nitrogen and sulphur. The proportions of the elements are constant in any given substance, but are not exactly the same in all. The limits of variation are, how- ever, very narrow, and in no case does the com- position of the compounds differ much from the following, which may be taken as the average for the group. Chemical Composition of Albuminoids. Per cent. Carbon . . 52-2 Hydrogen 7-2 Oxygen . . 231 Nitrogen . . 15-9 Sulphur . . . . 16 100-0 Most of the albuminoid compounds are practically insoluble in water, but some of them, like white of egg, are soluble. Others, though insoluble in pure water, are soluble in solutions of salt and other reagents. They may be precipitated, redissolved and even crystallized ; they form many curious compounds, and exhibit various interesting pro- perties. They all undergo a curious transformation called coagulation, which profoundly affects their properties, but does not materially alter their com- position. The setting or hardening of eggs on boiling, curdling of milk, and clotting of blood are familiar examples of this change. Coagulation may be caused by heat, by certain reagents, e.g. alcohol, tannin, etc., and by certain ferments such as rennet. THE CHEMISTRY OF NUTRITION 29 All albuminoids, soluble or insoluble, coagulated or uncoagulated, are converted into peptones by the action of pepsin — the ferment of the gastric juice. They are thus rendered readily soluble and diffusible and, therefore, capable of absorption by the villi. Peptones belong to, and exhibit the characteristic properties of the albuminoid group. When albuminoids are burned they are com- pletely oxidized ; the constituent elements — except nitrogen which is liberated in the free state — unite with oxygen, and carbonic acid gas, water and oxide of sulphur are formed. For 100 parts of the dry substance, 175 parts of oxygen, in addition to what it already contains, are required to complete the change. The oxidation of albuminoid compounds which takes place in the course of animal respira- tion is not complete — the nitrogen appears in the form of urea ^ — and only 148 parts of oxygen are required. There are many different kinds of fat, e.g lard, tallow, butter, palm oil, linseed oil, etc. Some are of animal, and others of vegetable origin, but they all resemble each other, more or less closely, in composition and general properties, and all belong to the same class or group. There is no essential difference between fats and oils. Those which remain liquid at ordinary tem- peratures are generally called oils, and the more solid are called fats. The solid fats melt at com- paratively low temperatures, and in that state are indistinguishable from oils. These compoimds are not so complex as the albuminoids ; they contain neither sulphur nor nitrogen. Only three elements — carbon, hydrogen ^ Urea is represented by the chemical formula NaH^CO- 30 ECONOMY OF FOOD and oxygen — enter into their composition ; they are always united together in a similar manner, ^ but the proportions vary slightly in different members of the group. Three of the commonest fats — ^known respectively as olein, stearin and palmitin — contain the elements in the following proportions : — Olein. Stearin. Palmitin. Carbon Hydrogen .... Oxygen (Percent.). 773 11-8 10-9 (per cent. ). 76-9 123 10-8 (per cent.). 75-9 12-2 119 100-0 100-0 100-0 It will be seen that the differences in composition are comparatively slight, and that, in all three cases, carbon forms more than three-fourths of the whole. The fats and oils are all insoluble in water and in salt solutions. They are dissolved by the action of strong alkalis, which converts them into soap and glycerine. Under certain conditions, they can be so intimately mixed with water that they remain in a state of semi-permanent suspension, without losing the essential properties of fats. Such mixtures are called emulsions ; they are most readily formed in slightly alkaline solutions. * The pure fats are all glycerides of fatty acids. Stearin, one of the commonest, may be represented by the chemical formula C3H5(Ci8H3502)3. The natural fats are, for the most part, complex mixtures of such glycerides. Butter contains at least nine different compounds of this kind. THE CHEMISTRY OF NUTRITION 31 When fats are burned, or otherwise oxidized, carbonic acid gas and water are produced. Each 100 parts of fat (stearin), require 292 parts of oxygen, in addition to what it, itself, contains, to com- pletely oxidize it. Fat, it will be seen, combines with nearly twice as much oxygen as an equal weight of protein when oxidized in the animal system. The carbohydrate group also includes a large number of compounds, some of which are externally very dissimilar. They are characteristically vege- table products ; starch, cellulose and some others are exclusively so. Sugars and one or two other compounds are produced by animals as well as plants, e.g. sugar of milk. There are several kinds of sugar besides the ordinary table sugar. The latter is generally called cane sugar, or sucrose, even when derived from beet. Milk sugar ^ resembles cane sugar very closely, but is not quite so sweet to the taste. The sugars commonly found in fruits and vegetables are of a different character, though similar in appearance and general properties ; they are called glucose^ and fructose.^ All sugars are soluble in water, and can be directly assimilated by animals without change of any kind. When yeast grows in a solution of sugar, the latter is converted into alcohol and carbonic acid. This change takes place in the manufacture of beer ; it is called alcoholic fermentation. Starch ^ is produced in larger or smaller quantities by nearly all plants, and is an important constituent ^ Cane sugar and milk sugar are represented by the chemical formula C12H22OH ; glucose and fructose, by the formula CgHi20g. ^ Starch, cellulose, dextrin and mucilage are all repre- sented by the chemical formula CgH^oO^. 32 ECONOMY OF FOOD of potato tubers, cereal grains and many other foods. It is made up of minute granules, and under the microscope, it is seen that these vary in size and exhibit peculiar markings which are charac- teristic of the plant from which the starch is derived. There is, however, no difference in the chemical composition, and very little difference in the pro- perties of the several kinds of starch. Starch is insoluble, and is not affected by cold water ; but when it is treated with boiling water, the grains swell up, lose their characteristic struc- ture, and form a khid of paste or jelly. The starch, however, is not even then dissolved. When heated in the dry state to a certain temperature, starch is converted into dextrin,^ the common gum used for postage stamps. By the action of certain ferments such as those found in saliva, in malt, etc., and also by the action of dilute acids, starch is resolved into glucose, a kind of sugar which, it has been said, is soluble, fermentable, and can be directly assimilated. The conversion of starch into sugar by the action of ferments is called diastatic fermentation. The change is an essential part of the process of di- gestion of starchy foods. Dextrin and mucilage undergo a similar change. Cellulose ^ has the same chemical composition as starch, but, except in very young plants, it is practically indigestible, and is consequently of little or no value for nutrient purposes. Notwithstanding the differences in the proper- ties of sugars, starch, mucilages and cellulose, noted above, they possess certain properties in ^ Starch, cellulose, dextrin and mucilage are all repre- sented by the chemical formula C^HioO^. THE CHEMISTRY OF NUTRITION 33 common, and these are characteristic of the whole carbohydrate group. They are composed of the same chemical elements as the fats, viz., carbon, hydrogen and oxygen, but in very different propor- tions. They do not, however, differ much from each other in this respect, as may be seen from the following examples : — Starch. Cane Sugar. Glucose. Carbon Hydrogen .... Oxygen .... (per cent.). 44.4 6-2 49-4 (per cent. ). 421 6-4 51-5 (per cent. ). 40-0 6-7 53.3 100-0 100-0 100-0 The carbohydrates undergo oxidation even more readily than the fats, but the products are the same, viz., carbonic acid and water. As they contain a relatively larger proportion of oxygen than the latter, a smaller quantity of that substance is required to consume them. Thus, 100 parts of starch combine with 118 parts of oxygen, 100 parts cane sugar combine with 112 parts of oxygen, and 100 parts of glucose combine with 107 parts of oxygen. It will be seen, therefore, that, on the average, 100 parts of carbohydrate require 112*5 parts of oxygen, in addition to what they contain, to completely oxidize them. It has been previously shown that 148 parts of oxygen are required to oxidize 100 parts of protein and 292 parts to oxidize 100 parts of fat. In other words fat consumes nearly twice as much oxygen 34 ECONOMY OF FOOD as an equal weight of protein, and 2 J times as much as an equal weight of carbohydrates, in the process of oxidation. Now, when a substance is oxidized, heat is given out. If oxidation take place rapidly, as in burning, a high temperature results ; but if it take place more slowly, as in respi- ration, the tempera- ture will be corres- pondin gly lower. The amount of heat produced, however, is the same in both cases. For sub- stances of the same kind, the amount of heat evolved depends upon the amount of oxygen they con- sume. The heat of com- bustion, i.e. the heat of oxidation, can be determined by means of an apparatus, called a calorimeter, of the kind shown in the illustration ^ (Fig. 2). The results are expressed in calories. A calorie is the amount of heat required to raise the temperature of 1 gram, of water 1° C. The following average results have been ob- tained : — ^ Bui. 21, U.S. Dept. of Ag. Fig. 2. Section of Bomb- calorimeter. THE CHEMISTRY OP NUTRITION 35 1 gram, protein yields 5,700 calories. 1 „ fat „ 9,500 „ 1 „ carbohydrate „ 4,100 „ It will be seen that these figures bear very nearly the same relation to each other as those showing the amount of oxygen consumed. As protein is not completely oxidized in the body, it consumes less oxygen and consequently gives out less heat than is shown above. The heat of combustion of the products (urea) must, therefore, be deducted in order to obtain the physiological heat value. Taking the average of a great many determinations, Riibner puts the physiological heat value of protein at 4,100 calories, i.e. the same as that of the carbohydrates. Atwater's estimate of 4,400 calories is probably the more accurate, but Riibner 's is the one commonly used. The calorie is inconveniently small, and it is usual to take the kilo-calorie as the unit for physio- logical purposes. A kilo-calorie is 1,000 calories. On this basis the factors become 9-3 for fat and 4-1 for carbohydrates and protein. Kilo-calories may be designated by the symbol " Kal." The facts quoted above — especially those relat- ing to the composition and oxidation of the com- pounds, protein, fat and carbohydrates — are of fundamental importance in regard to the phenomena of nutrition. These compounds are the principal constituents of food. It is from them that the tissues of the body are built up. The heat produced by their ultimate oxidation, maintains the temperature of the body and furnishes the energy required for the perform- ance of all the internal and external work. 36 ECONOMY OF FOOD Some physiologists speak as if the compounds were directly oxidized in the blood. It is more probable, however, that they are first changed into actual tissues which are subsequently oxidized. The point is one of considerable interest, but it need not be discussed here, as it makes no difference to the amounts of oxygen which they can ultimately consume, or to their potential capacities as heat pro- ducers ; in other words, it does not affect the nutritive or food value of the compounds. It has been shown that fat and carbohydrates are composed of the same chemical elements. They do not resemble each other very closely, but each can be formed from the other. As constituents of food, they perform the same functions in the body. Both are used to form fatty tissue which undergoes oxidation and so provides the heat and energy for the performance of work ; but any excess over what is required, remains unaffected and forms an addition of fatty tissue to the body. Fat and carbohydrates are not, however, of equal value for these purposes. According to Riibner their heat-producing values stand in the relation of 93 to 41 (vide ante) or 2 J to 1, and they bear a like relation as tissue (fat) formers. Some authori- ties ascribe an even higher value to the fat. They consider 1 lb. of fat equal to 2 J lb. of carbohydrate, but that is probably too high for the average. It is evident that fat and carbohdyrates cannot be changed into protein, for they lack the elements nitrogen and sulphur, which are essential constitu- ents of the latter. It has been clearly demonstrated that the protein of animal bodies is derived from the protein of the food. One kind of proteid may be transformed into THE CHEMISTRY OF NUTRITION 37 another, but cannot be formed from non-proteid.^ The amomit of protein in the food must, therefore, be sufficient to make good the loss of protein from the body ; otherwise the animal will gradually lose weight and will ultimately die of starvation, i.e. nitrogen starvation, however much of the other constituents may be present. But protein, like other constituents of the food, also undergoes oxidation and gives out heat — its fuel value is given above — ^and it is believed that ^ Many foods contain a number of other nitrogenous compounds such as gelatin, amides, etc., which are more or less closely allied to protein but cannot be ranked as true proteids. These are certainly of lower nutritive value ; it was formerly believed, and many recognized authorities still hold, that they have no nutritive pro- perties. Recent researches have, however, tended to throw some doubt on this point. When protein, is decom- posed by chemical means it is resolved into glycocine C2H5O2N ; leucine CgHigOsN, tyrosine C9H11O3N, cystine C6Hi204N2S2, and other bodies all belonging to the amino- acid group and commonly called amides. Protein may be split up in a similar manner by prolonged action of ferments, and it is considered probable that such disinte- gration actually takes place in the process of digestion, the proteids being subsequently re-synthesized, after absorption, in the walls of the intestine. In that case it should be possible to maintain life by the ingestion of these products, and evidence is not wanting to show that this can be done. Gelatin alone, has been proved to be insuf- ficient because it contains no tryptophane, tyrosine or cystine radicles ; but when administered along with certain amino-acid bodies, it has been found to maintain life. Dogs and rats have been kept alive for consider- able periods on a mixture of aminoacids without gelatin. The total nitrogen of all ordinary foods is therefore usually reckoned as protein, though it is probably true that the amides have a lower nutritive value than true proteids. This does not apply to gelatin, meat extracts and some other substances which are not ordinary foods. 38 ECONOMY OF FOOD fat is produced from excess of protein when enough of the other constituents is present to provide all the energy required. This change is theoretically possible, and it certainly takes place in some cases, but recent experiments have made it doubtful whether it occurs under normal conditions. In any case, however, it is not the proper function of protein to make fatty tissue. Still less is it the proper function of protein to furnish heat, but there is no doubt that if the food be deficient in fat and carbo- hydrates, protein will be oxidized to furnish the energy required. This, then, is another function of the non-nitrogen- ous constituents of the food, viz., to spare or save the protein from oxidation, and it is of the highest importance to see that it is fulfilled. Protein is the most expensive constituent of the food ; pro- tein tissues are formed more slowly than fat, and if subjected to excessive oxidation, loss of body weight results. CHAPTER IV QUANTITY OF FOOD Talking of a man who was grown very fat, so as to be incommoded with corpulency ; he said, " He eats too much. Sir." Boswell : "I don't know, Sir ; you will see one man fat who eats moderately, and another lean who eats a great deal." Johnson : " Nay, Sir, whatever may be the quantity a man eats, it is plain that if he is too fat, he has eaten more than he should have done. One man may have a digestion that con- sumes food better than common ; but it is certain that solidity is increased by putting something to it." Boswell: "But may not solids swell and be distended ? " Johnson : " Yes, Sir, they may swell and be distended ; but that is not fat." BoswelVs Life of Johnson. It has been shown in the preceding chapter that the nitrogenous and non-nitrogenous constituents of the food have different functions. Neither can be substituted for the other, nor can they act pro- perly, independently of each other. It may, there- fore, be laid down, as a fundamental principle, that a certain amount of each is necessary for bare sub- sistence, and additional quantities are required for work, growth or production of any kind. It is necessary, therefore, to inquire, not only what total quantity of food, but also what kind of food, is suitable under various conditions. The 40 ECONOMY OF FOOD two questions are really one, and must be considered together. In short, what we have to discover is, how much protein, and how much fat and carbo- hydrates are necessary and desirable in each case. The quantitative methods by which the require- ments of the body are investigated fall, broadly, into two classes, viz. (1) observations upon the quanti- ties of food consumed by individuals, and (2) obser- vations upon the products of metabolism given off or excreted from the body, under various condi- tions. It cannot be said that either of the two methods is entirely satisfactory ; and it is only by comparing the results of numerous experiments made in both ways that we can hope to arrive at an approx- imation to the truth. The evidence obtained by the second method is, perhaps, the more reliable as a primary indication ; but it must be controlled and confirmed by experiments made according to the first plan. The nitrogenous compounds — chiefly urea — re- sulting from the oxidation of protein in the body, are excreted in the urine ; the amount of nitrogen so excreted in a given time is, therefore, a measure of the rate at which oxidation of the protein takes place. The estimation of urea is a simple process. A measured quantity of urine is introduced into a tube or small bottle, and mixed with excess of sodium hypobromite ; the urea is completely oxidized by this substance, and the free nitrogen gas liberated by the reaction, is collected and measured ^ in a ^ For detailed description of the process, and also for an account of other and more accurate methods, the reader is referred to any of the numerous works on quantitative chemical analysis. QUANTITY OF FOOD 41 graduated tube. A form of apparatus (Dupre's) commonly used for this purpose, is shown in the illustration ^ (Fig. 3). Since protein contains 16 per cent, of nitrogen, the weight of this element multiplied by VV- = 6-25 gives the corresponding quantity of protein. The carbonic acid gas, which is exhaled from the lungs, can also be collected and measured by means of an apparatus known as the respiration calori- meter. This apparatus may also be made to serve other purposes in connex- ion with experiments of this kind ; but it is much too complicated to be described here. A general view of the respiration calorimeter used by At- water is shown in the illustration 2 (Fig. 4). The quantity of carbonic acid exhaled shows the amount of carbon oxidized. This carbon is derived mainly from the fat of the body, or, indirectly, from the fat and carbohydrates of the food. A certain ^^^^ Appabatus (Dupb^). Fig. 3. ^ Messrs. Baird » 13 „ At 6 „ >» 16 „ At 9 „ >» 19 „ At 12 „ »> 22 „ The examples given in the footnote ^ show how the formula may be used to calculate the diet correspond- ing to the standard for individuals of various sizes. In cold climates, cold weather, or as a result of exposure, the body loses more heat by radiation, and more fuel is required to maintain it. Men who spend much time in the open air, e.g. farmers, soldiers, fishermen, require more food than engineers, factory hands, tailors and others whose work may be equally hard but is done in dry warm rooms. Builders and workmen eat more when engaged on sea walls, high towers, or other exposed positions. Driving in motor cars and open carriages increases the appetite for the same reason, viz. because it promotes loss of heat by radiation. Clothes help to maintain the warmth of the body by diminishing radiation, but if the clothing be insufficient the body will demand more food. In very warm cli- ^ (a) For a man 5 ft. 10 in. in height, normal weight 12 stones. 12x14 = 168 lb. Protein : 0-02 x 168 =3-36 oz. Fuel value : [(18-7 x 168)- 3-3 (168- 150)] - 3,141-6- 59-4 = 3,082-2 kal. (b) For a woman 5 ft. 2 in. in height, normal weight 8 stone 2 lb. 8 St. 2 1b. X 14 = 114 lb. Protein: 0-02 x 114=2-28 oz. Fuel value : [(18-7 x 114)- 3-3 (114 - 150)] = 2,131-8 + 118-8 =2,250 kal. 52 ECOlSrOMY OF FOOD mates or under any conditions that tend to diminish radiation, less food is necessary. It is impossible to say what additions should be made to the food under these various circumstances. The quantity is generally determined by the appe- tite, and it apparently makes little difference whether the heat be derived from protein, fat or carbohydrates, or from a mixture of the three. Protein is the most expensive, and for other reasons it is probably undesirable to increase the quantity of this constituent beyond a certain amount — say 5 or 6 oz. per day at the outside. Carbohydrates are the cheapest source of heat, but are compara- tively bulky, and having regard to the amount pre- scribed in the standard diet, it is not generally desirable to make very large additions. Under conditions of extreme cold or exposure, such as those which obtain in the Arctic regions, the addi- tional food generally consists largely of fat. There are also, no doubt, other reasons for this. There is some difference of opinion regarding the additions that should be made to the diet of a man when doing work. In this connexion, the term work includes all forms of exercise and mus- cular effort, whatever their object may be. Formerly, it was held by Liebig and others that bodily work is accomplished at the expense of the muscular tissues, i.e. of the protein. This opinion was, apparently, founded on the fact that the work is accomplished by contraction and relaxation of the muscles ; but it does not foUow that the energy which causes them to contract is derived from oxi- dation of their substance. The work of an engine is done by the forward and backward thrust of the piston ; but the energy which produces the move- QUANTITY OF FOOD 53 ment is derived from the combustion of fuel, not of the iron of which the piston is composed. At any rate, Liebig's view is no longer tenable. When a man does bodily work, very little, if any, more protein is oxidized than when he is at rest, and the whole amount is not, as a rule, sufficient to account for the energy expended. On the other hand, a much larger amount of oxygen is absorbed, and a larger amount of carbonic acid is respired. The natural conclusion, therefore, is that the energy for the performance of bodily work is de- rived mainly, if not entirely, from the oxidation of non-nitrogenous matter, and that the quantities of fat and carbohydrates in the diet should be increased when the man does work. It has also been argued, from these premises, that it is unnecessary to in- crease the allowance of protein. Experience shows, however, that men doing hard work exhibit a strong desire for more nitrogenous diet, and that such diet appears to markedly increase the capacity for work ^ both of men and beasts. It was forbidden by the Law to " muzzle the ox that treadeth out the com.'' Almost every recognized authority considers that the quantity of protein — ^as well as that of the non- nitrogenous nutrients — ^should be increased when the man does work. The additional quantities ^ It is not easy to account for this ; but in the absence of more reliable information, it may be attributed to the stimulating effects of the dissociation products into which the protein is rapidly resolved. Similar effects have been observed to result from the direct ingestion of such com- pounds in the form of meat extracts. As stimulants, the latter have been found to be much superior to alcohol ; they have been largely used for soldiers on the march, and are said to greatly increase the men's power of endur- ance. 64 ECONOMY OF FOOD recommended vary from about 25 to 35 per cent, of the quantity for simple maintenance of the in- dividual in question, i.e. about 1 oz. for an average man. It is also generally agreed that the additional quantity of non-nitrogenous matter should be pro- portional to the work done ; but it is not easy to determine exactly what the amount should be in any given case. A simple calculation ^ shows that 326-4 kal. of energy is required to perform 1,000,000 foot pounds of work, which is reckoned a fair day's work for a man. But when bodily work is done, a considerable amount of energy is also expended in other ways — chiefly in evaporation of water — ^and this, also, must be allowed for in the diet. In one experiment, a man on average diet exhaled 281 grams more carbonic acid, and evaporated 769 grams more water, when at work than when at rest. The carbonic acid is equivalent to 98 grams of fat, i.e. to 915 kal. The water evaporated accounts for 462 kal. Add to this 326 kal. for work done, making a total of 788 kal., and there remains 127 kal. still unaccounted ^ for. Further consideration leads to the conclusion that, from 800 to 1,000 kal. of energy must be ex- pended in order to perform 1,000,000 foot pounds of work, and the additions should be sufficient to ^ 772 ft. lb. of work is the mechanical equivalent of the heat required to raise the temperature of 1 lb. of water 1° F., i.e. to raise the temperature of 453*59 grams f ° C, = 0-252 kal. Therefore, 0-252 x 1,000,000 = 326-4 kal. 772 ^ In this experiment, the amount of oxygen absorbed did not correspond with that of the CO2 and it is probable that the latter is too high. QUANTITY OF FOOD 65 produce this amount. The standard diet for a working man should, therefore, be as follows : — Standard Diet for Work. Protein. Fuel Value. For simple maintenance Additional for work .... 7 1 kal. 2,800 800 Total diet for work . . . 4 3,600 Many other experiments might be mentioned and criticized, but it will be sufficient to quote the conclusions arrived at by several authorities. ^ Standards for Daily Diet of Labouring Men. Nutrients in Food. Fuel Authority. Value. Protein Fat. Carbo- hydrates. oz. oz. oz. kal. Playfair (England) . . 4-16 1-76 18-72 3,140 Atwater (U.S.A.) . . 4-48 27-5-3 19-36 3,500 Moleschott (Italy) . . 4-64 1-44 19-36 3,160 Wolff( Germany). . . 4-48 1-28 19-04 3,030 Voit (Germany) — For moderate work 4-16 1-92 17-60 3,055 „ hard work . 5-12 3-52 15-84 3,370 Mean 4-51 2-32 18-32 3,209 1 Year Book, U.S. Dept. of Ag. 1894. 66 ECONOMY OF FOOD It will be seen that in most cases the amount of protein is higher and the fuel value lower than that given above. The average of all is probably not far from the truth ; but it must be remembered that it is only a standard, suitable for an average man, subject to modification in particular cases. It is a matter of common experience that some individuals consume much larger quantities of food than others. No doubt some men eat too much, and others too little ; but recorded observations show that, under exactly similar conditions as regards size, work, etc., the quantities of food consumed by apparently normal individuals vary considerably ; and it must be assumed that the quantities correspond approximately with the re- quirements, because the weights of the persons remain practically constant. Also, under like con- ditions, some men grow fat and others thin on quantities of food that are found to be just sufficient to maintain average individuals without gain or loss of weight. The question of the difference between individuals is a very difficult one and involved in obscurity ; but the more important facts are clear and simple. If a man consume one pound of food, his weight will be increased, for the time being, by that amount. Very soon the water will be eliminated, and, to- gether with a trifling quantity of salts and other substances, wiU be discharged in the urine. Of the solids a portion is indigestible, and will in time be dejected as faeces. The remainder undergoes oxi- dation, more or less rapidly, and the products are given off as gases. If more food be consumed than is oxidized in the same time, the excess remains and adds to the body weight, and vice versa. In short, QUANTITY OF FOOD 57 the weight of the body can remain constant only when the total outgoings are exactly balanced by what is taken in. In normal cases, water passes through the body so quickly that it scarcely affects the weight, and may, therefore, be ignored. There may be some difference in individuals as regards the power of absorption, but it is generally considered that such differences are not very great — certainly not enough to account for the observed differences in the quan- tities of food consumed. It appears, therefore, that these differences must be referred to the rate at which oxidation takes place. Oxidation is effected by the action of the lungs, which may be compared to that of a bellows blowing a fire. The larger the bellows and the more rapidly it is worked, the greater will be the quantity of air driven into the fire, and the more rapidly will the fire bum. So it is with the lungs. Some men have larger lungs, and some use them more efficiently than others. In some cases, too, the action may be more or less rapid than in others. Physiologists may, perhaps, trace this to the action of the heart, and ultimately to the nervous system, by which the whole of the functions of the organism are con- trolled. However this may be, it is obvious that in aU these cases the amount of oxidation taking place in a given time will be affected ; and that the quan- tity of food required by the individual will vary accordingly. Whatever the rate of oxidation in any given in- dividual, he will require more food when he does work than when he is at rest ; he wiU require more food when subject to exposure, and so on. Large individuals require more than small ones 68 ECONOMY OF FOOD because, as a rule, they have correspondingly larger lungs. Such, however, is not always the case, and sometimes small men consume more food than those of larger size. If a person desire to increase his weight, either the rate of oxidation must be reduced, or the quan- tity of food consumed daily must be increased. The former is not, as a rule, either practicable or desirable. Any addition to the food may be useless unless it be of the right kind. When a man, in a normal state of health, gains weight, the increase is made up of about 70 parts of fat, 20 parts of water, and 10 parts of protein, per cent. An increase of 24 lb, in a year is at the rate of 2 lb. per month, or, say 1 oz. per day. To pro- duce this increase, therefore, the person must absorb about 0'08 oz. of protein and 0*7 oz. of fat or its equivalent in carbohydrates — say 6*5 kal. — in addi- tion to what is required for his maintenance and work. In other words, the additional food should contain about 9 parts of fat to 1 of protein. To produce a larger or more rapid increase of weight, larger quantities must be allowed. In the case of a person whose weight is much below the normal, such as a convalescent, or one who is much " run down," the proportion of protein in the additional food should be larger ; in extreme cases, it may be as high as one of protein to one of fat. In order to reduce weight, either the rate of oxi- dation must be increased, or the quantity of food must be reduced. Increased oxidation results from increased work or exercise, and by aU conditions which promote radiation, e.g. light clothing, cool rooms, cold bathing, etc. QUANTITY OF FOOD 59 In the case of an individual whose weight is above the normal, the loss of weight consists mainly of fat. Thus it is estimated that in the case of a reduction of 20 lb. weight, about 14 lb. would be fat, 1*6 lb. protein, and the remainder water. Such a reduction might, therefore, be expected to result in greatly- increased activity as the person would have so much less mass to move. In the case of athletes, the slight reduction of the muscular tissues would pro- bably be more than compensated by the increased contractile power due to the training. When weight is reduced much below the normal, a more considerable loss of protein is involved, and loss of power results. It will be seen, therefore, that if it be necessary or desirable to restrict the allowance of food in order to effect a reduction of weight, it is chiefly the proportion of fat and carbohydrates that should be diminished. In general, the best and quickest results will be obtained by combining both methods, i.e. by increasing the rate of oxidation and at the same time restricting the quantity of food. The question of obesity di£Pers in some respects from that of an ordinary gain or loss of weight. It is further considered in a later chapter. In pregnancy, the rate of growth of the foetus is not uniform throughout the period, but for simplicity it may be assumed to be so. A full grown, well- nourished infant weighs at birth from 7 to 9 lb. The process of maturation occupies approximately nine months ; let it be 9 lb. in nine months, or, roughly, 1 lb. per month, i.e. about half an ounce per day. Of this quantity, at least 60 per cent, is water, and the remainder is made up mainly of protein and fat in about equal proportions. We 60 ECONOMY OF FOOD may take it therefore that about 0*1 oz. of each of these constituents ^ is required for the growth of the foetus, and the ordinary diet of the mother must be increased accordingly. During the period of lactation, a healthy mother yields from 20 to 40 oz. of milk ^ per day ; the quan- tity gradually increases with the requirements of the child, from the first to about the ninth month. From the second to the sixth month the average jdeld is about 30 oz. per day. The milk contains about 2" 3 per cent, of protein, 3*8 per cent, of fat, 6*2 per cent, of sugar, and 87 per cent, of water. These quantities are, therefore, equivalent to 0*7 oz. of protein and 600 kal. per day, and the diet for maintenance of a nursing mother must be increased by these amounts. Corresponding to the amount of milk produced, the additional quantities of food may be rather smaller at first, but should be gradu- ally increased, and, after the sixth month, should be greater than those calculated above. To calculate appropriate diets for a woman under these conditions, we may take the normal weight of the mother as 130 lb., i.e. the average weight of a woman 5 ft. 4 in. in height. The maintenance diet, calculated according to the formula (p. 50) is as follows : — Protein : 0-02 x 130 = 2.6 oz. Fuel value: (18-7 x 130)- S-B (130- 150) =2,431 + 66 = 2,497 kal. O-l oz. fat X 28 X 9-3 = 26 kal. 1 According to medical authorities the deposition of material in the fcetus takes place at the rate of about 3 grams of protein and 3^ grams of fat per day during the last three months of pregnancy (O'loz. = 2*8 grama). - Pfeifer. QUANTITY OF FOOD 61 Diet for Pregnancy. Diet for Tiactation. Protein. Fuel Value. Protein. Fuel Value. For maintenance . Additional . oz, 2-6 0-1 kal. 2,497 26 oz. 2-6 0-7 kal. 2,497 600 Total 27 2,523 33 3,097 It will be seen that lactation constitutes a much heavier drain upon the physiological resources of a woman than pregnancy. In fact, the fuel value of the food required is not much less than some of the estimates for the diet of working men. Of course, if the woman be called upon to do bodily work during the periods of pregnancy or lactation — ^as she generally is — still further additions must be made to the diet on that account, as previously shown. The dietetic requirements of children are not the same as those of adults ; they are governed by the same general principles, but allowance must be made for growth and greater activity, as well as for difference in stature and power of digestion. Not only do individuals differ considerably in all these respects, but also, any given child varies from year to year. The formula previously given for adults is not, therefore, applicable to children. For young children, an indication of their require- ments is afforded by the compositionl^of mother's milk. This, it has been shown, yields about 0*7 62 ECONOMY OF FOOD oz. of protein and 600 kal. fuel value per day. Assuming that this is adequate nourishment for a child of six months, weighing, say 16 lb., the requirements of children may be estimated at about 0'044 oz. of protein and 37-5 kal. per lb. weight per day. These quantities, it will be seen, are almost exactly twice as much as are required for simple maintenance of adults (p. 48). During the first five years, the diet of children should consist very largely of milk, and whatever is given along with it, the whole should furnish the quantities of nutrients indicated above according to the size (weight) of the child. From the age of ten to fifteen years, the diet of children should gradually approach that of adults in composition ; but having regard to the restless active character of children of that age, it is the diet for work, rather than that for simple mainten- ance, that it should be brought to resemble. The diet of children between the ages of five and ten years should be of intermediate character. In other words, from the age of five years upwards, the proportion of non-nitrogenous nutrients may be gradually increased ; but of course, the total quantity of protein must be augmented in proportion to the growth of the child. The following are the averages of some of the numerous diets which have been prescribed for healthy children by various authorities. QUANTITY OF FOOD 63 Nutrients in the Food. Fuel Protein. Fat. Carbo- hydrates. Value. Age 1- 2 years ,, 2- 6 „ „ 6-15 „ oz. 0-96 1-92 3-20 oz. 1-28 1-44 1-60 oz. 2-72 7-04 14-08 kal. 765 1,420 2,040 No doubt the diet of children is often deficient in protein ; but the proportions of that constituent in the diets given in the table seem unnecessarily- large. In the three cases quoted, it is respectively at the rate of 1*25, 1'35 and 1»57 oz. of protein to each 1,000 kal. fuel value, whereas in mother's milk, the proportion is only M5 oz. of protein to the 1,000 kal. The quantities of both nitrogenous and non-nitrogenous nutrients must be increased according to the growth of the child, but the pro- portion of protein to non-nitrogenous matter need not be increased ; on the contrary, it may be slightly diminished. Taking the weight of a boy of fifteen years of age as 100 lb., and calculating from the diet for work for adults, we get, after adding an allowance for growth, 2-7 oz. of protein and 2,636 kal. fuel value as the appropriate diet. This, it will be seen, is practically at the rate of 1 oz. of protein to 1,000 kal., which is probably sufficient. SECTION II. FOOD CHAPTER V CLASSIFICATION AND GENERAL PROPERTIES OF FOODS Next to the market places that I spake of stonde meatte markettes, whether be brought not only all sortes of herbes, and the fruit of trees with breade, but also fishe, and all manner of iiii footed beastes, and wilde foule that be mans meate. More's Utopia. Man is, in practice, omnivorous, using both animal and vegetable products as food. The former includes all kinds of butcher's meat, poultry, game, fish, the so-called shell fish, eggs, dairy produce, cured, canned and preserved goods such as bacon, lard, sausages, etc. To the latter belong fresh, dried and preserved fruits and vegetables, legumes, cereals and farin- aceous products, certain vegetable oils, sugar, molasses, jam, etc. The common beverages, tea, cocoa, ale, wine, and also spices and condiments, are nearly all of vege- table origin. These products, however, are not generally valued for the nourishment they contain — ^the proportion is usually very small — ^and it is GENERAL PROPERTIES OF FOODS 65 only by an extension of the term that they can be regarded as foods. The character of a food depends upon the digesti- bility of the nutrients — ^protein, fat and carbo- hydrates — ^it contains, and upon the actual and relative proportions in which they are present. The fat and carbohydrates, since they perform similar functions in the animal economy, may be grouped together. The nutritive values of these constituents, however, are not the same ; they stand in the relation of 9*3 to 4*1 or 2* 27 to 1. In order to express the ratio of nitrogenous to non-nitrogenous nutrients in a food, the fat and carbohydrates must, therefore, be reduced to the same denomination. By a generally accepted convention, this is accomplished by multiplying the percentage of fat by 2*27 ; the percentage of carbohydrates is then added and the sum is divided by the percentage of protein. This ratio is called the nutritive ratio of the food.i In the natural state, the foods always contain, in addition to the nutrients, a certain amount of water, some proportion of mineral salts, and also other compounds, which, either on account of their chemical nature or indigestible character, have no nutritive value. When the non-nutritive parts are unedible, e.g. feathers, bone, cartilage, skin, entrails, potato ^ Example, to find the nutritive ratio of a sample of milk which contains 3-5 per cent, protein, 3-6 per cent, fat, and 4-88 per cent, sugar — (3-6 X 2'27) + 4-88 _ 1305 _3-73 3-5 3-5 1 The nutritive ratio is I — 3-73. 66 ECONOMY OF FOOD peelings, stones of fruit, husk of grain, etc., they are wholly or partially removed in preparing the food for the market and for the table, and finally set aside as refuse. The amount of such refuse must be taken into account in comparing the prices and composition of different foods. The indigestible fibre of cereals and many other vegetable products is not unedible, and cannot be entirely separated from the nutrient constituents ; it cannot therefore be regarded as refuse, though it is practically of that nature. By removing the non-nutritive parts, the food is rendered more concentrated, and the percentage digestibility is increased. Medical men are, how- ever, inclined to regard this as a very doubtful advantage ; at least they consider that the process is, nowadays, rather overdone. Animal foods are generally rich in protein, and, as the latter is always associated with a large pro- portion of water, they undergo decomposition very readily. They cannot, as a rule, be preserved by simply drying — ^it is very difficult to drive off the water without spoiling the food — but must be treated with salt or some other antiseptic for this purpose. With very few exceptions, the non-nitrogenous nutrients of animal foods consist entirely of fat ; this constituent is generally present in larger or smaller amount, but the proportion is very variable. Apart from the unedible portions, the digestibility of animal foods is very high ; for most of them it may be taken roughly as 100 per cent. In general, animal foods are more expensive than those of vegetable origin. Of the vegetable foods, some, e.g. fresh fruits GENERAL PROPERTIES OF FOODS 67 and vegetables, contain a very large proportion of water, while others, e.g. cereals, etc., are sold in a comparatively dry state. The former decompose readily, but the latter may be kept in good condition indefinitely. As compared with the animal foods, they generally have a somewhat lower nutritive ratio, though some of them, owing to the comparatively dry condition, contain a larger proportion of protein. The non-nitrogenous nutrients consist mainly of carbohydrates — chiefly starch and sugar — but a few vegetable foods contain considerable propor- tions of fat. The latter are generally relatively deficient in carbohydrates. The fibre which is present in all plants, and, therefore, in most vegetable products, consists of cellulose and belongs to the carbohydrate group (p. 32). Except in very young and tender plants, it is practically indigestible, and is not, therefore, included with the total carbohydrate in estimating the nutritive value of the food. Certain kinds of cellulose undergo chemical changes in the intestines and gaseous products ^ are evolved. The production of intestinal gases is chiefly due to this cause. The digestibility of vegetable products is con- siderably lower than that of animal foods ; in ordinary cases, it varies from about 75 to 85 per cent., and may be taken, roughly, as about 80 per cent, of all the nutrients in the edible part of the food. The composition of plants, especially of the vegetative organs — roots, stems and leaves — ^is very variable. It depends largely upon the age, i.e. ^ Chiefly hydrogen and methane. 68 ECONOMY OF FOOD tlie stage of growth of the plant. Those parts which are always taken at or about the same stage of growth, e.g. fruit and seeds, are more nearly constant, but the composition of these also is affected by the ripeness, conditions under which they have been gathered, etc. Vegetable foods are, generally, much cheaper than animal products containing a like amount of nutrients. The price of food fluctuates from time to time, and varies in different locaHties ; it depends upon the quality of the goods and usually also, to some extent, on the quantity purchased. For example, apples are often quoted at 2d. per lb. or 7 lb. for \s. ; oatmeal is priced at IJ^Z., 2d. and 2^d. per lb. according to quality. In this case, and in many others, the quahty is purely a matter of taste ; the nutritive value of the cheapest does not differ perceptibly from that of the most expensive. Sometimes, however, it is otherwise. The prices quoted in this section are the retail prices current in the London Stores for high class goods in their proper season. ^In the case of butcher's meat, the prices are for good quality English meat ; chilled or frozen meat from foreign and colonial sources can be obtained at rates about 20 to 30 per cent, lower. CHAPTER VI BXJTCHER'S MEAT Home from my office to my Lord's lodgings, where my wife had got ready a very fine dinner — viz., a dish of marrow bones ; a leg of mutton ; a loin of veal ; a dish of fowl, three pullets and a dozen of larks all in a dish ; a great tart, a neat's tongue, a dish of anchovies ; a dish of prawns and cheese. Pepys' Diary. Butcher's meat consists of the carcasses of oxen, sheep — including veal and lamb — ^and pigs, to gether with the edible portions of the viscera such as kidneys, liver, etc. Other animals, e.g. deer, goats and horses, are sometimes used, but they are not considered here. BEEF The weight of oxen varies, according to the breed, age and condition of the animals, from about 1,000 lb. to 1,500 lb. In general, the weight of a well fed ox, three years old, is about 1,200 lb. when it comes into the hands of the butcher. The animal is killed by bleeding ; the pelt and the abdominal and thoracic viscera are re- moved, and the head, tail and lower joints of the limbs are cut off. The weight of the dressed car- cass is then about 600 or 800 lb., i.e. about 60 69 70 ECONOMY OF FOOD per cent, of the total live weight. By cutting radially through the middle of the back bone, the carcass is divided into two equal parts, called " sides of beef,'' each of which may weigh from 300 to 400 lb. The anterior portion, including the ribs, is known as the fore quarter, and the remainder — the posterior portion — ^as the hind quarter. The former weighs from 110 to 160 lb., and the latter from 200 to 260 lb. In some cases they are divi- ded so as to be of nearly equal weights. The method of cutting up the quarters for retail varies slightly in different localities, but the common practice in this country will be understood from the illustration (Fig. 5). Fig. 5. The hind quarter is divided into (a) the leg, (b) round, (c) aitchbone, (d) rump, (e) thick flank, (/) thin flank, and (g) sirloin. The forequarter com- prises (h) fore rib, (^) middle rib, (j) chuck, (k) brisket, (l) clod, (m) shin, and (n) neck or stick- ing piece. Legs and shins are very similar in composition and quality. They weigh from 10 to 20 lb. each. BUTCHER^S MEAT 71 and are sold at 5d. per lb. If a portion of the adja- cent cuts is included, higher prices are charged. About half the total weight of these pieces is bone ; they are used chiefly for making stock for soups, and meat jellies. The meat is rather hard and strong tasted, but is practically free from fat ; it may be purchased separately at about 7d. per lb. When properly cooked, it makes excellent stew. The upper part of the hind limb, called the " round,'' includes the great thigh bone and the meat attached to the same. The whole piece weighs about 40 or 50 lb. including some 3 or 4 lb. of bone. The meat is usually very lean, but is too hard for first quality. The portion from the inside of the leg is the more tender, and is distinguished as the topside, as it generally lies uppermost in the shops. The topside may amount to about 25 lb. weight, and is sold at 9d. per lb. for the whole piece or lOd. per lb. in cuts. The middle portion is more highly esteemed than either end, and a higher price — usually lO^d. per lb. — is charged for it. The outside portion of the leg, commonly called the silver side, weighs from 20 to 24 lb. and is sold at 8(i. per lb. for the whole piece or 9d. for prime cuts. The round yields good boneless roasts and beef steak. The silver side is often pickled for boiling. The aitch bone is a wedge-shaped joint taken from between the round and the rump. It weighs about 14 or 16 lb., including from 2 to 2 J lb. of bone, and is sold at Q^d. per lb. ; smaller pieces, including a larger proportion of bone, are sold at 6d. per lb., and those of larger size, including portions of the round or rump, and, therefore, having a smaller proportion of bone, are more expensive. The meat is not, as a rule, very fat ; it is fairly tender and 72 ECONOMY OF FOOD makes good roasts, but it is esteemed of second quality. The rump, as a whole, weighs from 26 to 30 lb., including from 3| to 5 lb. of bone. The meat of this portion is slightly fatter than that of the round ; it is of first quality and very tender. It is sold at lO^d. per lb. for the whole piece or lid. for the top end (i.e. the anterior end). Smaller cuts, e.g. rump steaks, are charged at Is. 2d. per lb. ; these of course are free from bone and unedible parts. The term sirloin is commonly applied to the whole of the loin piece, amounting to about 30 or 40 lb., between the rump and the ribs. It includes from 3 J to 4 J lb. of bone, and is sold at lie?, per lb. for the whole piece or Is. per lb. for prime cuts. In some localities, the anterior portion is known as the small end of loin or short steak, and the term sirloin is reserved for the posterior end next the rump. The middle portion, including the larger part of the undercut and the kidney suet, is known as the tender loin. Porterhouse steaks are cut from this part and sometimes also from the small end, but the sirloin is chiefly used for roasting. The meat is all of first quaHty and resembles that of the rump, but is generally rather leaner. The thick flank piece weighs from 24 to 28 lb. It contains no bone, but the sinew and unedible matter amounts to about J lb. The meat is ranked as second quality, i.e. as inferior to the rump and sirloin, for roasting, but it is a prime boiling piece, and is often salted or corned. It can be obtained for Sd. per lb. for the whole piece or 9J^. in cuts. The thin flank is of markedly inferior quality, and, as it is not easily sold, the whole piece, weighing BUTCHER^S MEAT 73 from 20 to 26 lb., may be purchased at 5d. per lb. or 5^d. for smaller cuts. It contains no bone, but from 2 to 10 per cent, of it is unedible ; it is chiefly used for sausage making and similar purposes. The edible portion is not unduly fat or strong tasted and, minced or stewed, it makes excellent food. At the price mentioned, it is by far the most " profitable " portion of beef. The rib cuts weigh, altogether, from 35 to 50 lb. The finest part, known as the wing ribs, is cut from the posterior end, i.e. next to the sirloin, and is sold at Is. per lb. From this forward, the proportion of bone gradually increases, and the prices are correspondingly lower. The middle portion, commonly called the fore rib, is the largest ; it weighs from 24 to 30 lb., including from 5 to 6 lb. of bone, and is sold at lid. per lb. The anterior portion, about 12 or 16 lb., known as the middle or back rib, is sold at about 8^d. per lb. The rib cuts are prime roasting pieces. The meat is tender and of excellent flavour ; it is often cut off from the bone and rolled. The chuck or top ribs, as it is sometimes called, amounts to about 12 or 16 lb., but if a portion of the shoulder is included, it may be more. The whole piece may be bought at 8^d. per lb., including bone, but it is chiefly sold as steaks of second quality at lOd. per lb. In the brisket, about 4 or 5 lb. out of a total weight of 18 to 22 lb. is bone and unedible matter. The meat is tender but rather fat, and is chiefly used for salting and boiling. It costs about Td. per lb. in small cuts, but the whole piece may be pur- chased at 6jc?. per lb. The neck and clod contain a large amount of 74 ECONOMY OF FOOD bone and unedible matter, and are chiefly used for making stock and gravies. They are sold at 5d. or Qd. per lb. The term clod is sometimes used by butchers in a different sense. VEAL The term veal is generally understood to refer to the flesh of calves, but as there is no particular age at which they are killed, it is rather indefinite, and both the weights and the composition of the joints are consequently very variable. Veal is in season only from February to November, and it is best in the summer months. It is not cut up in exactly the same manner as beef. The average prices of the principal joints of veal are as follows : — Hind Quarter. Price per lb. Fore Quarter, Price per lb. (a) Hock . . . Qd. (e) Breast Shd. (6) Fillet . . . Is. Id. (/) Neck(best end) lO^d. to (c) Loin (best end) lOd. Is. (d) „ (chump (g) „ (scrag) . Qd. end) 9d. (h) Shoulder. . Sd. (i) I^uckle . 6d. The hock, sometimes called the hind knuckle, is the lower part of the leg ; the fillet is the upper part of the leg and corresponds to the round of beef ; the portion known as the best end of loin includes the rump, and the chump end is the loin proper ; the best end of the neck is really the ribs or chuck, and the scrag is the anterior portion inclu- ding the neck proper ; the knuckle, sometimes BUTCHER^S MEAT 76 called the fore knuckle, corresponds to the shin of beef. MUTTON Mutton, like beef, is nominally in season all the year round, but it is best from September to April. During the summer months, its place in the market is largely taken by lamb. The total live weight of sheep, like that of oxen, varies with the breed, age and condition of the animal, from about 100 to 150 lb. ; the average is about 120 lb. The weight of the dressed carcass is usually about 60 or 80 lb. Mutton is cut up for retail in a very simple manner. The hind quarter is divided merely into the leg and the loin ; the two loin parts, when un- divided, are known as the saddle of mutton. The joints of the fore quarter are the shoulder, breast and neck. The neck, so called, really includes the ribs or chuck, and the posterior part is known as the best end ; the anterior portion, or neck proper, is called the scrag or top end. Legs weigh from 8 to 10 lb. each ; of this from IJ to 1| lb. is bone. Smaller joints are often charged at higher rates, but the average price is about lOd. per lb. Loins weigh from 7 to 9 lb. The proportion of bone is rather less than in legs, but the meat is fatter, and the price is usually higher, viz. from lOd. per lb. for the whole piece to Is. Id. per lb. for the best end, trimmed. Shoulders weigh from 6 to 8 lb., and cost from Sd. to 9d. per lb. The meat, like that of the leg, is lean, but the proportion of bone is large, amounting in some cases to a quarter of the total weight. 76 ECONOMY OF FOOD The best end of the neck, usually about 4 or 5 lb. weight, is sold at 10^. per lb. It is not quite so fat as the loin, but includes a larger proportion of bone — ^about 3 oz. per lb. The top end of the neck, or scrag, contains about 4J oz. bone to the lb. but is not so fat. It weighs about 2 or 3 lb. and is sold at 6d. per lb. The breast includes the lower ends of the ribs and about 10 per cent, of the whole is unedible. The meat is very fat, and as it is not much appre- ciated, is sold at 4:d. per lb. Mountain sheep, e.g. the Welsh and Cheviots, are usually smaller than the common English breeds. The meat is very lean, dark coloured, and possesses a rich flavour that is much appre- ciated. Such mutton is, therefore, generally quoted at higher prices. The properties mentioned appear to be due, in large measure, to the fact that the sheep are mountain bred, and are, therefore, half starved and very active. It is certainly a fact that when these sheep are reared on rich lowland pastures, they grow much larger and fatter, and the mutton is scarcely distinguishable from that of the common English breeds. Mutton from Wales, it wiU be seen, has not necessarily the qualities of " Welsh Mutton '* unless it be mountain reared. LAMB Lamb is in season only from March to September, though it may be had at other times of the year. It is best from May to July ; when very young it is apt to be flabby and tasteless, and when more than six months old, it resembles mutton, but has not the firm texture and rich flavour of the latter. BUTCHER^S MEAT 77 As in the case of veal, the weight, composition and price of the various joints vary with the age of the animal. The following are about the average prices in the month of August. Hind Quarter. Whole, Leg. Loin lid. Is. lid. per lb. Fore Quarter. Whole. Shoulder Breast . Neck . 9ld. per lb. llc^. „ Id. „ nd. „ PORK Fresh pork is in season only during the winter months, and is at its best from November to March. Pigs are killed at different ages and varying degrees of fatness, and the weight consequently varies within much wider limits than does that of sheep and oxen. The very large and fat animals gener- ally go to the curers ; of those killed for fresh pork, the live weight may run from about 80 to 400 lbs. The hind quarter includes the leg and the hind loin ; the fore quarter comprises the foreloin, the hand or shoulder, the belly or spring and the head. In the leg and hand, from 10 to 12 per cent, of the total weight is bone, and usually from J to J of the meat is fat. In the loin cuts, the proportion of fat is about the same, but the proportion of bone and unedible matter is nearly double. The belly part, or 78 ECONOMY OF FOOD spring, contains no bone but about 1 oz. in each lb. is unedible and usually more than half the meat is fat ; it is very often pickled and boiled. In this country, pork is eaten perhaps more largely in the cured than in the fresh condition. It is subjected to a process of salting, either with dry salt, or by steeping in brine, and sometimes smoked. It is then commonly known as bacon ; this term, however, is sometimes applied exclusively to the body or trunk portion, and the hind limb is distin- guished as ham, but the " side of bacon " generally includes the ham or gammon as it is called. Bacon is not cut up quite in the same manner as fresh pork, and the various cuts are known in the trade by dijfferent (i.e. special) names. The three principal parts of the side are the fore-end, middle and hind end, and these are subdivided as shown in the illus- tration (Fig. 6). The average weights and prices of the pieces are as follows : — BUTCHER'S MEAT 79 Piece. Average Weight. Average Price per lb. A. Fore End— 1. Collar 2. Forehock B. Middle— 3. Thick streaky .... 4. Thin streaky .... 5. Flank 6. Back and ribs .... 7. Long loin C. Hind End — 8. Corner of gammon . 9. Gammon lb. 8 8 8 4 3 8 7 4 10 d. n 5 n 7 7 Whole side 60 8^ COMPARISON The several kinds of meat — beef, mutton, pork, etc. — exhibit strongly marked differences of colour, odour, and flavour, which render them more or less agreeable to certain individuals. Certain kinds of meat are apt to disagree with some persons, and it is often said that these are less digestible. It is probable that they do differ to some extent in digesti- bility, i.e. in the length of time required for com- plete peptonization, but the differences have prob- ably been greatly exaggerated. Lamb and veal are softer in texture than mutton and beef, and it is commonly believed that they are more readily digestible. There is very little certain information on this subject, but such as is available tends to cast doubt upon the popular notions. 80 ECONOMY OF FOOD It is true, in general, that the meat from old and poorly-fed animals is harder and more difficult to masticate than that from younger and better fed beasts, and it may be therefore concluded that it is not so easily digestible. It is not true, however, though it is very generally believed to be, that the softer and more tender kinds of meat are of a more watery and less nourishing character than that from more mature animals. On examination of the tables in the appendix, it will be seen that the proportion of water in the vari- ous kinds and cuts of meat is very variable — it depends largely upon the proportion of bone and fat they contain — but the ratio of water to protein is approximately constant. The ratio is about 33 to 1 in aU kinds and cuts of meat, and is nearly the same in fat and lean portions ; in veal it is a little higher, viz., about 3*5 to 1, but in lamb it is slightly All kinds of fresh meat must therefore be re- garded as practically alike in this respect, but cured meats are often different ; smoked bacon, for in- stance, is a partially dried product, and contains only about 2 parts of water to 1 of protein. The proportion of bone in the different portions of meat is chiefly of importance from the point of view of pecuniary economy. The proportion of fat is, perhaps, of less importance in that connexion but, to a large extent, it determines the character of the meat and the dietetic purposes for which it is suit- able. Of course, much depends upon the condition of the beast in this respect, but it may be said that, in general, beef is leaner and pork is fatter than mutton ; and that lamb and veal are not so fat as mutton and beef respectively. 82 ECONOMY OF FOOD The proportions of bone, fat and lean in various pieces of meat are shown in the illustration (Fig. 7). SUNDRIES Under this head may be included all those organs, etc., which, though not part of the carcass proper, are sometimes used as food. Ox-tails contain nearly a third of their weight of bone, and it is difficult to separate the meat entirely from it. They are used practically only for making soup, to which they impart a peculiar flavour that is much esteemed. Ox-tails cost from Is. 3d. to Is. Qd. each. A much larger amount of shin or other stock meat could be obtained for a similar expenditure. Ox tongues vary in size from about 4 to 6 lb. The meat is lean, but rather tough, and about a fourth of the whole is unedible. They are usually pickled, but may be eaten fresh, and are almost invariably boiled. The price of fresh tongues at the butchers is about 2s. Qd. or 35. 6d. each; when pickled they are more expensive. Sweetbreads — ^the pancreatic glands — ^are es- teemed a rare delicacy. The meat is soft, easily masticated, and is supposed to be readily digestible. It contains about 4 parts of water to 1 of protein, i.e. considerably more than ordinary meat. A pair of good ox sweetbreads, free from unedible matter, weigh about f lb. and are sold at Is. Qd. Lamb sweetbreads weigh about 2 oz. and cost about 2d. each. Those of sheep are smaller and cheaper. Kidneys are found attached to the loins, and when sold separately, are usually dissociated from the fat in which they are always embedded, even in lean animals. The meat is practically all lean, but BUTCHER'S MEAT 83 unless very carefully cooked, is apt to be hard — al- though it contains about 4 J parts of water to 1 of protein — and is considered rather indigestible. Ox kidneys weigh from about 1 lb. to 1 J lb. each and cost about Is. per lb. Those of sheep and pigs are smaller — ^from 1 to 2 oz. — and are sold at 2d. to 3d. each. Ox kidneys, as purchased, generally include a certain amount of unedible matter. Liver somewhat resembles kidneys in appearance and in chemical composition, but differs markedly in flavour and other respects. Ox liver is very rarely used as food for human beings. Sheep's liver weighs from 1| to 3 lb. and can be purchased for about 5d per lb. Lamb's liver is more expensive owing to the greater demand for it. Ox hearts weigh from 4 to 6 lb., and cost about 2^. each. The meat contains a considerable proportion of fat, and as it is very hard and unpalatable, it is rarely used as food for human beings. Sheep's hearts weigh from 6 to 8 oz. and cost about 2d. or 3d. each. In chemical composition, they resemble ox hearts, but are not quite so tough. They are generally sold along with the lungs and liver, the whole being known as a " sheep's pluck." The lungs or lights, as they are called, weigh about 4 or 5 oz. ; the meat is lean and resembles ordinary meat in composition, but is considered not very agreeable in taste. The price of the sheep's pluck is about Is. or Is. 3d. each. AU these tough meats are rendered more readily digestible when minced or reduced to the j&nely shredded condition of potted or sausage meat ; they may then be well salted, spiced and mixed with breadcrumbs, and so rendered more palatable. Tripe is the substance of the large receptacle or 84 ECONOMY OF FOOD first stomach of the animal. The total quantity obtainable from a full grown ox is about 10 or 12 lb. It is cleaned and dressed by the butcher, and is sold, free from unedible matter, at Qd. per lb. It is practically free from fat,^ and, by prolonged boiling, may be rendered very tender. It is, how- every, watery in character; it contains about 7| parts of water to 1 of protein, i.e. more than twice as much as ordinary meat. In other words, one pound of tripe contains less nourishment than half a pound of lean beef steak or other meat free from bone. Suet is the name commonly given to the kidney fat of oxen and sheep ; that of pigs is generally known as lard. Beef suet, as purchased, contains a certain amount of non-fatty matter, but the fat generally amounts to over 80 per cent., and moisture to 10 or 12 per cent. It is sold at Td. per lb. Mutton suet, sometimes known as tallow, contains a larger proportion of moisture and non-fatty matter, and is sold at 5d. per lb. Pork fat is derived both from the back and belly parts. It is some- what softer, i.e. it melts at a lower temperature, than suet, but it contains about the same pro- portion of fat. When refined, all the impurities are removed, and the pure leaf lard contains nothing but fat. ^ According to Atwater's analyses, pickled tripe con- tained only 12 p.c. of fat, but canned tripe contained 8*5 p.c. For tripe purchased at the butchers, other authori- ties give the proportion of fat as from 10 to 15 p.c. CHAPTER VII POULTRY, GAME AND FISH It is observed by the most learned physicians, that the casting off of Lent and other fish days (which hath not only given the lie to so many learned, pious, wise founders of colleges, for which we should be ashamed) hath doubtless been the chief cause of those many putrid, shaking, intermitting agues, unto which this nation of ours is now more subject than those wiser nations that feed on herbs, salads and plenty of fish ; of which it is observed in story, that the greatest part of the world now do. And it may be fit to remember that Moses (Lev. xi. 9 ; Deut. xiv. 9) appointed fish to be the chief diet for the best commonwealth that ever yet was. The Compleat Angler, POULTRY The weight of common fowls runs from about 3 to 5 lb. each. The unedible matter, consisting of the feathers, head, lower joints of the legs, entrails and bones, form, altogether, about a quarter of the total live weight ; the entrails alone, not including the giblets, weigh from 6 to 8 oz. In chickens, the proportion of unedible matter is larger ; in very young birds, it may amount to more than half the total weight, but in the plumper and more mature birds it is not so much. The meat of chickens is 85 86 ECONOMY OF FOOD very lean — ^much leaner than that of grown fowls — but the proportion of water to protein in both, is about the same as in butcher's meat. The price of fowls is very variable ; for well-fed birds the average is about 35. each ; roughly about I5. per lb. The weight of turkeys varies from about 10 to 20 lb., though both larger and smaller birds can be obtained. Of those reared for the Christmas mar- ket, the average weight is about 12 or 15 lb. Turkeys are usually fed to a very plump condition and conse- quently the proportion of refuse is somewhat less than in common fowls ; the meat also is both fatter and drier. The price, at Christmas, runs from about lOd. to Is. Id. per lb. ; the average is about Is. The' meat of waterfowl — chiefly ducks and geese — ^also is drier than that of common fowls, and is much fatter. At Christmas, ducks weighing from 5 to 6 lb. are sold at 45. to 55. 6d. each, while geese, which weigh from 8 to 12 lb. each, are sold at about Sd. per lb. Rabbits weigh from 3 to 5 lb. each. The weight of the pelt is from 5 to 8oz.,and that of the entrails about the same. The carcass which remains when these parts are removed may be from 2 to 4 lb. weight, including the head ; the average is from 2| to 3 lb. Rabbits are generally sold paunched, i.e. with entrails removed, but with the pelts on. They fetch from I5. to I5. Qd. according to size. Austra- lian (frozen) rabbits may be had cheaper — ^from 9d. to I5. each. FRESH FISH Of the many different kinds of fisht hat are used as food in this country, those mentioned below are, perhaps, the most important. They are often classi- POULTRY, GAME AND FISH 87 fied as round and flat fish ; the distinction may be convenient for certain purposes, but it bears no more relation to the dietetic value than a division into large and small fish. The meat of fish is soft in texture, easily masticated, and, it is supposed, readily digestible. It contains, as a rule, more water to protein than butcher's meat — ^in some cases nearly twice as much — ^but salmon contains actually less, and herring, mackerel and some others, only a little more. These fish are frequently described as " rich '* ; this probably refers to the amount of fat rather than to the proportion of water they contain, but it might, in this case, be applied in either sense. Cod, haddock, hake and flounders are practically destitute of fat, and skate contains very little. The unedible parts of fish — entrails, tails, heads, skin, fins, bones, etc. — ^form a large proportion, usually more than half the total five weight. In flounders and some other flat fish it amounts to over 60 per cent., but in herrings and mackerel, it is not much over 40 per cent. Some fish vary in size within very wide limits ; the weights given below are only approximate aver- ages, both larger and smaller specimens being of common occurrence. The prices also are very vari- able ; those quoted are, except where otherwise stated, per lb., for the whole fish weighed before being cleaned, and are those normally prevailing when the fish is in season. Small fish, such as her- rings, flounders, and not infrequently mackerel, are usually priced at so much per fish, or per dozen ; in these cases, the price, per lb., has been calculated from the average weight. Some fish, e.g. skate and halibut are often so large that they could not be con- veniently sold whole, and the retail prices quoted are 88 ECONOMY ^OF FOOD for cuts only. Even in the case of the smaller speci- mens of skate, the whole fish is rarely exposed for sale because its appearance is considered very unattract- ive. The average weights and prices, and times when the fish are in season are as follows : — Fish. Average Weight. Season. Best. Price. lb. per lb. Haddock . 1-4 Aug. to Feb. Winter 5d. Cod . . . 6-20 Nov. to Mar. Feb. to Mar. 4d. ; tail cut, Qd. middle cut,8d Hake . . 8-16 Whole year Winter Same as cod. Flounder . i-1 »f Aug. to Nov. 4d. Plaice . . i-4 >> May to Nov. Qd to 7d. Herring i-U May to Jan. June to Sept. Id.-l^d. Mackerel . 1-3 Whole year Apl. to July 2d. Salmon . 10-25 Feb. to Sept. Summer 1/4 to 1/6 ; middle cut, 1/9 Turbot 4-12 Whole year *) lOd. to 1/- Skate . . 10-50 Sept. to April Oct. to Mar. Qd Halibut . 10-50 Whole year Nov. to Jan. 7d.;cuts,10d. CURED FISH Fish are cured by salting, smoking and drying. The larger kinds are usually first prepared by re- moving the entrails and cutting off the heads ; the amount of refuse is thereby greatly reduced. When the fish are dried, a larger or smaller proportion of the water is evaporated. The amount of nourishment in any given fish is not perceptibly affected by these processes, and when they are sold, like herrings for example, by the dozen, a cured fish may be reckoned simply as equivalent to a fresh one. But, when the fish are POULTRY, GAME AND FISH 89 sold, like cod, by weight, it should be remembered that there is a much greater amount of nourishment in a pound of the cured product than in a pound of the fresh whole fish. Herrings are pickled, i.e. salted, whole ; they are then called bloaters, and are sold at Is. to 2s. per dozen. When salted, dried and smoked they are called red herrings, and are sold at from Is to I5. Qd. per dozen. Kippered herrings have the entrails removed, but the heads are not cut off ; they are lightly salted and smoked, with partial drying. They cost from about Is. to 2s. per dozen. Haddocks are cured in a similar manner. They are cut open, the heads and entrails are removed and the fish are then lightly salted and smoked. In Scotland they are called Finnan haddocks, or Aberdeen haddocks, but in England they are gener- ally known as Scotch baddies, or simply baddies. Sometimes the skin and bones are also removed, leaving the " fillet '' free from refuse of any kind. These fillets are often highly salted, but are usually only lightly smoked — sometimes not at all — the beautiful golden colour being produced by a dye- stuff of some kind. London cured haddocks are sold from 5d. to l, w', I*'), and yolic (y). White Yolk Water. 86-2 49-5 Protein. 12-3 15-7 Pat. — per cent. 33'3 ,, ,, The average weight of hen's eggs is a little under 2 oz. ; they run about eight or ten to the pound, and cost anything from four to twenty-four for a shilling. In towns, the price is rarely under \d. each, which is equal to about ^d. per lb. Duck's eggs are slightly larger — about six or eight to the pound — and cost about \\d. each. Turkey's eggs are about twice and goose eggs three times the size of hen's eggs. When eggs are boiled, the proteids are coagu- lated, i.e. the contents change from a semi-fluid to a solid state. This change does not perceptibly alter the composition of the compounds, and does not affect the dietetic value unless the eggs are DAIRY PROOtlCE" ' " ' " ioi boiled very hard, when, of course, they are less readily digestible. Healthy adults, however, experience no difficulty in digesting even hard- boiled eggs if they are properly masticated. The extremely offensive odour of rotten eggs is due to decomposition of the proteids, which is caused by the action of microbes. The latter are so minute that they find entrance to the eggs through the pores of the shell ; but if they are excluded the eggs may be kept in good condition indefinitely. There are several methods by which this may be effected. One of the commonest is to paint the shell over with a solution of sodium silicate (water- glass) which blocks up the pores, and so hinders the entrance of bacteria. Vaseline and some other substances have been tried, but they are not so good as water-glass. Another plan is to bury the eggs in finely pow- dered slaked lime, or in common salt. These sub- stances exclude the air, and by their antiseptic action destroy the bacteria. They are sometimes used in the form of solutions. Lime has the dis- advantage that it acts on the substance of the shell and renders it very brittle. It is said also to im- part a disagreeable flavour to the eggs, but this is denied by many who have used the method. To be successful, it is, of course, necessary that the eggs should be perfectly fresh and clean to begin with. They should be first wiped and then dipped in hot water for a second or two before preserving. According to one authority eggs may be preserved by simply immersing them in boiling water for twenty seconds. This, it is supposed, destroys the bacteria, and coagulates a thin layer of albumen within the shell, which prevents the entrance of 102 ECONOMY OF FOOD others. Eggs packed in bran, sawdust or other substance which excludes the air, may be kept much longer than those packed in straw. Perfectly fresh eggs are semi-transparent, and when held up to strong light, exhibit a uniform rose tint without any dark spots. The air chamber, also, is small. A cloudy appearance gradually develops, becomes darker as the egg gets older and finally renders them opaque. At the same time the size of the air space increases. This is the best test of the freshness of eggs. CHAPTER IX VEGETABLE FOODS : CEREALS, FARIN- ACEOUS PRODUCTS, ETC. Bread of flour is good. Sesame and Lilies. The special characteristic of these foods is that they contain a large proportion of starch. The proportion of protein is variable but not, as a rule, very large, and that of the fats is generally small. As purchased, they contain relatively small amounts of water. The cereal grains, for instance, are comparatively dry when harvested ; they are further dried after cutting, and usually also again in the processes of milling and preparation to which they are subjected. In the grains of cereals the fat and protein are concentrated towards the exterior, i.e. in the region next the husk ; but as they are there associated with a large amount of fibre, the nutrients of that part of the grain are not so readily digestible. The exterior portions of the grain are, therefore, gener- ally separated in the process of milling, and are sold under the name of bran, pollards, barley meal, rice meal, etc., as food for cattle and poultry. The germ, which lies at the centre, consists largely of nitrogenous matter, but is very small. It is sur- 104 ECONOMY OF FOOD rounded by a thick coating of starchy matter, and it is this portion of the grain that is chiefly used as food. Wheat is by far the most important of the cereal grains. It is the principal bread stuff, and is also used in a variety of other forms. Over seven mil- lion tons of dressed wheat grain are consumed annually in this country, i.e. over 1 lb. per head of the population daily. Many different varieties of wheat are grown in different districts. Some of them are bearded ; some are red and others are white or yellow in colour. The composition of the grain is more or less characteristic of the variety, but varies within certain limits according to the climate, season, soil, and other conditions under which the plant is grown. The following results were obtained on analysis of 250 samples of wheat grown in different localities : — Composition of Wheat Grain. Protein . Fat . . . Carbohydrates Fibre . . Maximum. Minimum. per cent. per cent. 24-6 8-2 2-6 10 77-3 61-3 64 1-2 Average. per cent. 124 1-7 67-9 2-6 The proportion of nitrogenous matter (protein) is always greater in wheats grown in hot, dry cli- mates. Such grain is harder, denser, and more translucent in appearance than others which con- tain a larger proportion of starch. The latter have thinner husks and skin and yield a larger quantity CEREALS, FARINACEOUS PRODUCTS, ETC. 105 of fine flour on grinding, and the flour is more suit- able for making bread ; they are, therefore, deemed of better quality. Some samples of wheat yield as much as 80 per cent, of fine flour, and others only from 50 to 60 per cent. Wheat is subjected to a very elaborate process of grinding in order to obtain the finer qualities of flour. The finest flour is derived from the inner portions of the grain. It is whiter, more starchy and makes better bread than that derived from the outer parts. The latter is sold as second and third qualities. The bran is removed by processes of repeated grinding and sifting. The grain is some- times ground up whole after removal of the husks and skins. The product is called whole meal or wheaten meal, and is, of course, practically a mix- ture of bran and white flour ; it is, in fact, some- times made by mixing the two. At some mills, as many as ten different grades of flour are produced, but in this country the principal products are as follows Finest flour Seconds Middlings Tailings Sharps . Pollards Bran . Waste and loss 40 per cent. 18 12 8 9^18 „ 4 100 The various qualities of white flour do not differ much in chemical composition. They contain, as a rule, from 10 to 12 per cent, of protein, about 75 per cent, of starch and 1 per cent, of fat. When the starch is removed by the action of saliva, or in 106 ECONOMY OF FOOD other ways, a yellowish elastic substance called gluten remains behind. It consists mainty of pro- tein, and it is the presence of this substance which gives the cohesive plastic character to dough pro- duced by kneading flour with water. This is the principal difference between wheat flour and pure starch. Fine white flour of various makes may be pur- chased in sacks of 280 lb. at about l^d. per lb., in retail quantities at 2d., or usually 7 lb. for a shilling. The finest Hungarian, self-raising and patent flours are more expensive. Inferior grades are, of course, somewhat cheaper. Ordinary loaf bread is prepared, essentially, by mixing the flour with water, kneading the dough — ^yeast being added to make it "rise" — and then firing, i.e. baking, it. The effects of these processes are more fully discussed in a later chapter (p. 139), but it may be said now that the chemical changes, though important, are not very extensive. The composition of bread does not, therefore, differ much from that of the flour except in regard to the proportion of water it contains. This also constitutes the largest difference between one sample of bread and another. Fresh white bread usually contains from 35 to 40 parts of water, 8 or 9 of protein, from 50 to 60 of carbohydrates, and 1 of fat, per cent. Brown bread, made from whole meal, contains a slightly larger proportion of protein and fat. As compared with white bread the difference in nutritive value is small, but owing to the presence of the coarser elements — bran, etc. — it has a slightly laxative effect and is, therefore, preferred by people who are predisposed to constipation. CEREALS, FARINACEOUS PRODUCTS, ETC. 107 The quality of bread depends partly upon that of the flour, and partly upon the method by which it is made. Bread made from the cheaper qualities of flour is often darker in colour, and alum, copper salts and other substances are sometimes introduced to whiten it. All these compounds are, however, more or less deleterious to health, and their use is illegal. If excessive quantities of yeast are em- ployed, or if its action be unduly prolonged, the bread acquires a sour taste from the lactic acid which is formed. Such bread is rightly regarded as of inferior quality as the taste is disagreeable. It is not, however, at all injurious, nor is it neces- sarily less nourishing. The average price of bread is about l^d. per lb., but fancy loaves and those of finer quality are more expensive. Unleavened bread, and that made from other cereals, e.g. barley, rye, maize, etc., necessarily differ to some extent both in composition and properties. Macaroni, spaghetti, vermicelli and other similar products are made from harder varieties of wheat which are not suitable for making bread owing to the large amount of gluten they contain. The flour, which is prepared by a peculiar process, is mixed to a paste with water, moulded in the desired form, and dried by heat. For semolina, the paste is not moulded but simply dried hard and ground to a coarse meal. Shredded wheat has practically the same composition as whole meal, but owing to its peculiar mechanical condition, it is supposed to be more readily digestible. In the milling of barley, the product which remains after removal of the bran, is called pot 108 ECONOMY OF FOOD barley ; by further treatment this is converted into pearl barley. The latter costs about 2d. per lb. or 7 lb. for Is. ; pot barley is rather cheaper. Rice is not grown in this country — ^it requires a moist, warm climate — but is imported in large quantities. In appearance, the grain bears a certain resemblance to wheat and barley. Compared with these in point of composition, rice contains less pro- tein and fat. In the process of removing the bran from the exterior, some of the grains become bruised and broken ; these are separated and sold as ground rice at l\d. per lb. The whole grains, polished, are sold at 2d. per lb. Large grained varieties, used for curry, and certain special brands cost from 2\d. to 4:d. per lb. The many different varieties of oats may be broadly divided into two classes, viz. (1) the small and black varieties with thick husk and skin, used chiefly for feeding horses, and (2) the larger white varieties from which oatmeal is prepared. The com- position of the oat grain differs markedly from that of the cereals previously mentioned. Oats contain less starch and much larger proportions of fat and fibre. The fat is of a peculiar quality ; it contains a certain amount of free fatty acid (p. 30) which gives the grain its peculiar piquant flavour. Very little but the husk and skin is removed in milling, practically the whole of the grain being ground into meal. Oatmeal is sold in three grades known as fine, medium and coarse. These terms refer merely to the fineness of grinding and not to the quality. The superior quality of Scotch oat- meal is commonly attributed to the character of the grain grown in that country ; probably, how- ever, it is due, in large measure, to the skill of the CEREALS, FARINACEOUS PRODUCTS, ETC. 109 Scotch millers. English oatmeal often has a peculiar bitter taste, which is very disagreeable, and which may be due to over heating. Crushed and rolled oats have practically the same composition and properties as oatmeal. Maize is not largely employed as such, in this country, but a number of products derived from it are in common use. Of these, perhaps the most important are hominy and corn-flour. In making these products, the cereal is subjected to treatment with alkalis which extract a considerable part of the protein and fat, and leaves sometimes nearly pure starch. In England cornflour is also made from rice,^ but there is not much difference in the composition. Hominy costs about 2d. per lb. and cornflour, from 4cZ. to Gd. per lb. Sago, tapioca and arrowroot consist of practically pure starch of which they contain about 85 per cent., the remainder being moisture and a trace of mineral matter. Arrowroot is obtained from the tuberous roots of certain herbaceous plants (Maranta). The tubers are pulped and worked with water on a sieve through which the starch granules escape, and are thus separated from the fibre with which they are associ- ated in the plant. The starch is then collected, purified and dried in the sun. So prepared, the arrowroot imported from Bermuda commands the very high price of 35. 3c?. per lb., though it is prac- tically indistinguishable from that imported from St. Vincent, which is sold here at 4:d. per lb. Tapioca also is obtained from tuberous roots, but the plants belong to a different order. The starch is contained in the juice expressed from the ^ Bell, Chemistry of Food, 110 ECONOMY OF FOOD pulped tuber ; when washed with water and dried, it is known as cassava starch, or Brazilian arrowroot. This product is partially dried and exposed to heat, which causes the starch granules to burst and cohere in irregular masses ; this forms the tapioca of commerce which is sold at 3d. to 3|dl. per lb. Sago is obtained from still another kind of plant known as the sago palm, which often attains a height of over 30 ft. The starchy matter is found, not in the root, but in the stem. The tree is cut down and the pith is scooped out ; the starch is then separated from fibrous impurities by working with water on a sieve as in the case of arrowroot. When it is purified and dried, it is called sago flour. This is granulated by mixing to a paste with water and heating till the starch grains burst and cohere in granules on drying. Genuine sago is sold at 4:d. and 5d. per lb. Special qualities consisting of larger granules are more expensive. It is of a brownish colour, and has a peculiar earthy taste. Pearl tapioca is frequently sold under the name of white sago. This practice is not regarded as fraudu- lent, although tapioca is a cheaper product. The term legume is used in different senses. Here, it refers to the seeds of certain leguminous plants, of which beans, peas and lentils are the most im- portant. They are also known as pulse grains. As compared with the cereal grains, these seeds are distinguished by the presence of a much larger proportion of nitrogenous matter and a smaller proportion of starch. The three mentioned above are much alike in composition. Beans contain a slightly larger proportion of fat, and peas contain more woody fibre than lentils. This fact regarding peas lends colour to the popular notion that they CEREALS, FARINACEOUS PRODUCTS, ETC. 1 1 1 are apt to produce flatulence, and lentils are often preferred to peas on this account. Beans and peas are too well known to need any description. Lentils are, perhaps, less familiar. They are not grown in this country as the climate is unsuitable. The plant of which they are the seed somewhat resembles vetches in appearance. The ordinary varieties of peas, beans and lentils cost about 2d. per lb., but some special qualities are sold at 4:d. or 4^d. per lb. The various kinds of nuts in common use are all well known, and need no description. They are valuable foods, and are much esteemed by vegetarians, chiefly on account of the large propor- tion of oil they contain, but they are also fairly rich in protein. The composition is given in the tables in the appendix. They are considered somewhat indigestible, but it is said no difficulty is experienced when they are finely ground. In any case they should be thoroughly masticated. The following are the average prices of the commoner sorts : — per lb. per lb. Almonds . . . . Qd, Walnuts, . . . . 6d. Filberts. . . . . 6d. ,, kernels . . Is. Peanuts . . Sd. Brazil nuts . . . 6d. Barcelonas . . . . 4d. Cocoanuts . each 3d. Chestnuts . . . 3d. There are several different kinds of natural sugar, and many others can be prepared by artificial means. They are divided, by chemists, into groups. The various kinds of sugar used for domestic pur- poses all belong to the cane sugar group, and were formerly obtained exclusively from sugar cane. Large quantities are now obtained from beet. It is estimated that about two-thirds of the sugar 112 ECONOMY OF FOOD now on the market comes from this source. Beet sugar is practically identical with that derived from sugar cane, and as a rule no distinction is made commercially. The processes by which the sugar is extracted from the two plants, of necessity differ in detail, but in general outlines they are very similar. In both cases, the material is reduced to pulp, and the sugar is expressed in the juice or washed out with water. The grosser impurities are then removed, and the water evaporated until the sugar begins to crystallize. The product so obtained is called raw sugar, and the liquor which remains is called molasses or treacle. Kaw sugar from Demerara and Trinidad is some- times used without further refining. It is a soft, moist, easily soluble product, sometimes called brown sugar. It contains about 90 per cent, of pure cane sugar, 5 per cent, sugar of another kind, called invert sugar, and 5 per cent, of moisture. It is sold at 2ld. per lb. Certain inferior products of the refineries are sometimes dyed and sold as best Demerara. These consist of very small crystals, hold a large proportion of water, and have less sweetening power than raw sugar. ^ White sugar is prepared from the raw product by a very elaborate process of refining. The substance is dissolved in water, decolourized, purified and crystallized in vacuum pans. The vacuum pan is a device to make water boil at a lower tempera- ture, and it is used to prevent the sugar from being converted into an uncrystallizable form. It is impossible, however, entirely to prevent this change, 1 Bell, Chemistry of Food. CEREALS, FARINACEOUS PRODUCTS, ETC. 113 but the sugar which undergoes it is recovered and sold as golden syrup. The common granulated sugar produced by this process is almost absolutely pure and free from moisture ; it is sold at 2d. per lb. Loaf sugar is practically the same product crystallized in moulds, but as some manipulation is involved, the price is higher, viz., 2\d. to 3c?. per lb. Treacle and syrup are sometimes confused. The former term generally refers to the molasses obtained in the crystallization of raw sugar, but is occasionally applied to the syrup or drip obtained in refining. The viscous, black treacle or molasses, contains about 60 per cent, sugar, of which two- thirds is cane sugar, 10 per cent, protein and 30 per cent, water. It is sold at 2\d. to Zd. per lb. The molasses obtained in crystallizing crude beet sugar, is unfit for use as food. Golden syrup is lighter in colour than treacle, but is very similar in composition. Vegetable fats and oils are used to a considerable extent in the pure state, i.e. after extraction from the seeds, nuts or other parts of the plants which contain them. Olive oil is derived from the fruit of the olive trees, of which a number of different varieties are cultivated in the South of Europe, Asia Minor and elsewhere. The oil is obtained both from the fleshy part of the fruit and also from the stones. The former is much superior and is known as the " finest virgin oil (sublime).'' The latter has a slightly rancid flavour, and is often adulterated with cotton-seed, sesame and other cheaper oils. A low grade, mixed oil, is obtained by crushing the whole fruit and kernels together. Even the finest qualities rapidly go rancid when exposed to heat 114 ECONOMY OF FOOD and light, e.g. in shop windows. When pure, it should be of a light yellow colour, thin and almost tasteless. The French and Italian products are sold in this country at from Is. to Is. 3d. per pint, but the Spanish is dearer, about 25. per bottle. Cotton-seed oil and oil of sesame closely resemble olive oil ; they are used not only to adulterate it, but are often substituted entirely for it, both avowedly and fraudulently. The so-called salad oil generally consists of pure cotton-seed oil. It is sold at 10^. to Is. per pint.^ Almond oil, properly so called, is obtained by pressure, both from sweet and from bitter almonds, which contain about 50 per cent, of bland oil. It is not to be confounded with the volatile product known as oil of bitter almonds. The latter is of the nature of an essence and is obtained by dis- tillation after the fat has been expressed (p. 134). Pure almond oil is of a light yellow colour, thin and almost tasteless. It is one of the most expensive vegetable oils, being sold at from 2^. to 25. Qd. per pint, and is, therefore, frequently adulterated with cheaper oils. What is called peachnut kernel oil, but is in reality largely made from the stones of apricots, plums and other fruits, resembles almond oil. It is considerably cheaper and may be used in place of the latter ; as a matter of fact it is used to adul- terate almond oil and is sometimes fraudulently substituted for it. Araohis or peanut oil, which is also extensively used, has a somewhat disagreeable flavour similar to that of the nuts themselves, and which becomes more pronounced on standing some time. Peanut ^ A little over 1 lb, weight. CEREALS, FARINACEOUS PRODUCTS, ETC. 115 oil is fairly cheap, about 9d. to lOd. per pint, and enters into the composition of most of the so-called vegetable margarines or butter substitutes. The fundamental substance of the latter, however, is cocoanut oil. These vegetable margarines are sold at prices ranging from Sd. to Is. per lb. ^r' The vegetable oils, with the exception of the last mentioned products, consist of pure fat and are all of equal nutritive value. The butter^sub- stitutes contain from 10 to 12 per cent, of moisture. CHAPTER X FRUITS AND VEGETABLES .... entreat thy Lord that he give us what the earth produceth, beets, cucumbers, garUck, lentils and onions . ... Eat of the fruits of the earth. The Alcoran. Fresh vegetables generally consist of edible roots, stems and leaves, the composition of which is very- variable. They always contain a large amount of water. The dry or solid matter rarely exceeds 10 or 12 per cent, of the whole. It is composed mainly of carbo- hydrates. Either starch or sugar generally predominates, but a considerable amount of cellulose is always present. The last becomes fibrous and more or less indigestible as the plants get older, and in that condition, it is apt to produce flatu- lence and disagree with people of weak digestion. Fats are often absent, or occur only in negligible quantities. The nutritive ratio is generally low, and, of the total nitrogenous matter, a variable but usually considerable part is in the form of amides which have very inferior, if any, nutritive properties (p. 37). The true proteids also are less easily and less completely digestible than those of seeds. It is obvious, therefore, that the nutritive value u« FRUITS AND VEGETABLES 117 of fresh vegetables is small compared with that of the more concentrated foods previously mentioned. On the other hand they are relatively very cheap, i.e. when considered weight for weight. Many of them are more valuable for their hygienic properties than for any directly nutritive effects. As a rule, the corresponding parts of the plants exhibit a general similarity of composition, and they may be arranged in groups accordingly as follows — Boots. Turnips. Carrots. Beetroot. Parsnips. Radishes. Tubers. Potatoes. Artichokes. Leafbulhs. Onions. Leeks. Stems Seeds and and Leaves. Fruits. Cabbages. Peas. Spinach. Beans. Lettuces. Tomatoes. Celery. Marrows. Cauliflower. Cucumbers. Tubers are often classed as roots, but they are, in reality, underground stems, and their nutritive and other properties are very different from those of turnips, etc. Potatoes are the most important. They contain less water and more nutrient matter than any of the other vegetables mentioned. The carbohydrates consist mainly of starch, and the proportion of fibre is small. Potatoes form the staple diet of large numbers of people, and having regard to their composition, price, etc., they rank next to bread itself in this respect. Artichokes have a higher nutritive ratio than potatoes and are not much inferior in other respects. Roots are more watery. They contain only a small amount of nitrogenous matter, and of this, more than half is sometimes present in the form of amides. The carbohydrates, which consist mainly 118 ECONOMY OF FOOD of sugar, are the most important nutrients of these vegetables. Cabbages and other vegetables of that class are even more watery than the roots. From a fifth to a third of the total carbohydrates generally con- sists of fibre of a rather indigestible character, and except when the plants are very young and tender, these vegetables do not agree with many people. Cauliflowers have been put in the same group, but they are very different in character. The edible substance consists mainly of the unde- veloped flower buds ; consequently, the nutritive ratio is higher, and the proportion of fibre is smaller than in cabbages. In ordinary language, the term fruit is appHed only to vegetable products that are suitable for dessert, and peas, marrows, cucumbers etc., are regarded as fruits only in the botanical sense that they are the part of the plant that contains the seed. In the case of peas and beans, it is the pod that is the fruit, and though this is the edible part of French beans, etc., it is the seed alone of green peas that is eaten. The latter are, therefore, simply undried legumes and, apart from the water they contain, closely resemble those previously described. They have a high nutritive ratio. Fresh fruits are relatively very expensive and, as a rule, they are consumed only in comparatively small quantities. They are valued more on account of their pleasant flavours and hygienic properties than for the nourishment they contain. Protein generally forms about 1 per cent, of the edible matter ; and fats about half that amount. Some ol them, however, contain much smaller amounts FRUITS AND VEGETABLES 119 of the former, and some are practically destitute of the latter constituent. Carbohydrates occur in more variable but, usually, more considerable quan- tities. They are, in all cases, the most important nutrient in these products, and generally consist largely of sugar. In the unripe condition, most fruits are hard, sour and unpalatable ; but as they approach maturity, the cellulose becomes converted into the softer pectic compounds, the proportion of sugar increases, and the acids are partly changed into ethereal substances which impart the charac- teristic aroma to the fruit. The pectic compounds are soluble in hot water but insoluble in cold, and solutions, therefore, soHdify in the form of jellies on cooling. By the action of ferments which are present in the fruit, and also by prolonged boiling with water, the pectic compounds are changed into substances which are soluble in cold water and which do not, therefore, form jeUies. This is what occurs when fruit becomes over ripe. In the process of making jam, therefore, it is advisable to select fruit that is barely ripe. Boiling completes the process by which pectic compounds are formed, destroys the ferments and evaporates off some of the water so that the product sets well on cooling. But if the fruit be too ripe to start with, or if the boiling be unduly prolonged, the pectic compounds are destroyed, and the jam will not set. Fruits are preserved by drying, which either destroys the ferments or renders them inoperative. By abstraction of water, the proportions of all the nutrients are increased. Some of the dried fruits are highly concentrated foods, and have a fairly high nutritive ratio. Carbohydrates always 120 ECONOMY OP FOOD predominate, and, in some cases, amount to about 75 per cent. ; protein forms from 15 to 20 per cent, and fat from 2 to 4 per cent, of the edible matter. Dried fruits are used in puddings and in various other ways. If steeped for a few hours before using, they take up a considerable amount of water and are much improved in all respects. They are not so much esteemed for hygienic purposes as fresh fruits, but are an excellent substitute when the latter are unobtainable. Honey may be regarded as a vegetable rather than an animal product inasmuch as it is collected rather than produced by bees. It is probable, however, that the saccharine substances undergo modification in the honey bags of the bees. These creatures certainly have the power of transform- ing sugar into wax. Honey consists mainly of a mixture of several different kinds of sugars, with smaller quantities of wax, gum, poUen, formic acid and other organic substances. The flavour and odour of the honey depend largely upon the kind of flowers from which it has been collected. Bees fed on sugar or glucose produce large quantities of honey of very inferior quality. Glucose is used to adiflterate honey and is sometimes substituted for it, either fraudulently, or avowedly under the name of artificial honey. Genuine honey should contain not more than 25 per cent, of water. CHAPTER XI PREPARED FOODS: PACKET GOODS, PATENT AND PROPRIETARY ARTICLES If then plain bread and milk will do the feat. The pleasure lies in you and not the meat. Pope {''Satires''). Almost every variety of cereal, pulse and farina- ceous product is put up in packets and sold by various firms, either under their own or some registered fancy name. These goods are usually prepared from selected materials of fine quality. Many of them are mixed products derived from several sources, and they are often subjected to special processes of milling. Partly on this account, but perhaps more largely because the cost of the packets, packing and advertising must be borne by the consumer, packet goods are usually more expensive than similar products sold from bulk. The distinction between packet goods and patent and proprietary articles is rather a fine one. The latter term is generally understood to refer more particularly to those foods which are, or are supposed to be, specially adapted to the requirements of infants and invalids, as regards their composition and digestibiUty. They are very numerous, diverse in character, and can only be briefly noticed here. [ Patent and proprietary articles are relatively 121 122 ECONOMY OF FOOD very expensive. In some cases, the prices are ridicu- lously out of proportion to the cost of production ; but in others, the prices cannot be considered excessive when the methods of preparation and other circumstances are taken into account. The majority of those which have an established repu- tation are more or less suitable for their ostensible purposes. Apart from meat preparations — which are suitable only for adults — infants' and invalids' foods are mostly derived from cereals, or from milk, or a mixture of the two. They may be classified accord- ing to the nature of the product and the treatment to which it has been subjected. In cereal preparations, the grains are reduced to very fine flour, and all husks and bran are removed by repeated grinding and sifting. Some of them are disintegrated with water, cooked, dried, baked, and again ground. Others are merely well baked in the dry state. Baking destroys bacteria and fungi with which the grains are often infected, and converts some of the starch into dextrine. The last mentioned substance is soluble in water, and, therefore, easily assimilated. A large proportion of the starch, however, always remains unchanged. Several well-known foods belong to this tjrpe. Wheat is the cereal principally employed, but some contain an admixture of barley. Cane sugar, milk sugar, and dextrine are sometimes added to increase the amount of soluble carbohydrates. In certain cases, pulse flour and finely ground nuts are mixed with the cereals to increase the proportions of pro- tein and fat. Infants under the age of six months are unable to assimilate starch, and foods which contain a PATENT FOODS 123 large proportion of that ingredient are, therefore, unsuitable for them. Small quantities of starch are probably harmless, provided the infant is not starved for lack of other nourishment, but in large amounts it may be positively injurious. For this reason, a large number of the cereal foods intended for infants are prepared with malt, which promotes the digestion of starch. Malt may be described simply as sprouted grain. It is usually made from barley, but other cereals may be used. To prepare it, the grain is soaked in water, and then piled in heaps till the seeds germinate, i.e. begin to grow. It is then dried, and the growths are removed. Malt, so prepared, contains a large proportion of diastase — a, fer- ment closely resembling that of saliva — ^which in the presence of warm water converts starch into maltose and other soluble carbohydrates. The diastatic ferment is most active at temperatures of about 60° C. ; its properties are permanently destroyed by boiling water. The malted or predigested cereal foods contain active diastase mixed with tiie cereal flour, and the chemical change which the starch undergoes takes place when the food is in course of preparation for use. It is highly important, therefore, that the directions for the preparation of these foods should be followed exactly. In some malted foods, practically the whole of the starch is converted ; in others, a larger or smaller proportion remains unchanged. The latter are intended chiefly for older children. Malt extracts are prepared by grinding the malt to a coarse meal, and soaking in warm water. The solutions so obtained are usually concentrated 124 ECONOMY OF FOOD to a thick syrup containing about 25 per cent, of water ; in some cases they are desiccated. Besides the soluble carbohydrates of which they are chiefly composed, they contain a small amount of protein, and have, therefore, a certain nutritive value in themselves. They are chiefly used, however, in small quantities, to promote the digestion of starch in other foods taken at the same time. By removal of the starch from wheat and other cereals, the protein can be obtained in a fairly pure state. A product of this kind, sold under the name of gluten flour, is used for making " gluten bread '' for diabetics. A cheaper substance of the same kind, known as legumin or vegetable casein, is prepared from peas and beans. Other commercial varieties of vegetable protein are obtained from rape and other seeds, and are sold under various names. The processes by which special milk foods are prepared are of two kinds, viz. those which affect the digestibility of the milk, and those which affect its composition. Peptonized or predigested milk can be obtained commercially. There are many different brands. It is easily prepared at home by treating fresh milk with one of the peptonizing powders, of which several kinds are sold for the purpose. The composition of milk may be modified (1) by altering the relative proportions of casein, albumen, fat and carbohydrates, e.g. the so-called " humanized milk " previously referred to (p. 96), and similar products of which there are many varieties on the market ; (2) by concentration, e.g. condensed and desiccated milks ; (3) by a combination of both methods. PATENT FOODS 125 Condensed milk is prepared by evaporating off a portion of the water. The process is carried out at a low temperature, under diminished pressure, in order to avoid coagulating the albumen and spoiling the taste of the milk. The composition of the product depends upon the composition of the sample from which it is prepared, and upon the degree of concentration. Commonly, fresh whole milk is used, and is reduced to about half, or a third, of its original volume. The product therefore contains two or three times as much of all the nutrients as the original. A quantity of sugar is sometimes added. This product, called sweetened condensed milk, is sold at 5d. per tin ; the unsweetened variety is sold at 4:d. Condensed skim milk can also be obtained ; it is, of course, much cheaper. Sometimes a portion of the cream is fraudulently removed, but most of the well-known brands are fairly reliable in this respect. Desiccated milk may be regarded simply as condensed milk from which practically the whole of the water has been expelled. It may be made from whole, skim, or partially defatted milk. Cow and Gates brand is sold in packets (equal to 3 pints of whole milk) at 8d. " Glaxo " and " lacvitum " are similar products ; 1 lb. of the latter is said to be equal to about 6 pints of whole milk and costs about l» • 41-8 31-9 10-6 — 6-3 1,040 1-0-75 »> 37-6 29-5 22-5 — 6-5 1,498 1-1-73 StUton . 21-2 26-3 45-8 — 2-9 2,421 1-3-95 Gorgonzola — 40-3 27-7 26-1 — 6-3 1,616 1-2-10 * Calculated from Rubner '8 factors . t Total protein 3-6. X „ M 2-3. § Tota 1 non- fatty sc Uds. _-. 170 ECONOMY OF FOOD Refuse Water. Protein NX 6-25 Fat. Carbo- hydrates. Fuel* Ash. Value Iper lb. Nutritive Ratio. Per Per Per Per Per Per cent. cent. cent. cent. cent. cent. Eal. Eggs— Hen's. . . . 11-2 65*6 ll-9t 9-3 0-9 635 1-1-77 Turkey's . - 13-8 63-5 11-6 9-7 — 0-8 625 1-1-89 Duck's . . . 13-7 60-9 11-5 12-5 0-8 751 1-2-47 Goose's . . . 14-2 59-7 11.5 12-3 — 0-9 733 1-2-43 * Calculated from Riibner's factors, t Too low ? By difference 13-1. Appendix B COMPOSITION OF FOODS AS PURCHASED : VEGETABLE PRODUCTS Refuse. Water. Pro- tein. Fat. * Carbo- hydrates. Fibre. Asli. Fuel value per lb. Nutri- tive Ratio. Per Per Per Per Per Per Per cent. cent. cent. cent. cent. cent. cent. Kal. Wheat Dressed grain . 13-5 12-4 1-7 67-9 2-6 1-8 1,565 1-5-78 White flour . — 12-4 11-2 1-0 74.9 0-2 0-5 1,645 1-7-00 Whole- meal — 11-4 13-8 1-9 71-9 0-9 1-0 1,675 1-5-52 White bread . — 35-3 9-2 1-3 53-1 0-5 M 1,215 1-6-09 Brown bread (Graham) . — 35-7 8-9 1-8 52-1 M 1-5 1,210 1-5-98 Macaroni . — 10-3 13-4 0-9 74-1 — 1-3 1,665 1-5-69 Vermicelli . . — 11-0 10-9 2-0 72-0 — 4-1 1,625 1-7-02 Barley— Pot barley — 14-4 8-5 1-7 73-3 0-9 1-2 1,593 1-9-08 Pearl barley . — 11-5 8-5 M 77-8 0-3 M 1,650 1-9-45 Bice- Whole, -polished — 12-3 8-0 0-3 79-0 0-2 0-4 1,630 1-9-96 Ground rice — 11-5 8-1 0-3 79-4 0-2 0-5 1,640 1-9-89 Cornflour t (Brit.) Oats— Oatmeal — 13-0 2-1 — 84-6 — 0-3 1,612 1-40-29 7-3 16-1 7-2 67-5 0-9 1-9 1,860 1-5-09 Rolled oats . 7-7 16-7 7-3 66-2 1-3 2-1 1,850 1-4.95 Maize — Whole-mealJ . — 15-0 8-2 3-8 68-7 1-9 1-4 1,610 1-9-43 Hominy — 11-8 8-3 0-6 79-0 0-9 0-3 1,650 1-9-68 Cornflour . 12-6 7-1 1-3 78-4 0-9 0-6 1,645 1-11-45 „ §Oswego — 10-6 2-1 — 86-8 — 0-5 1,650 1-41-31 Prepared Starches Arrowroot . — 2-3 — — 97-5 — 0-2 1,815 — Tapioca — 11-4 0-4 0-1 88-0 0-1 0-1 1,650 — Sago . . . — 12-2 9-0 0-4 78-1 — 0-3 1,635 — » II ■ . . — 15-2 — — 84-6 — 0-1 1,570 — * Including fibre. f Bell, Chemistry of Food, compare maize, t Used as fodder. § Bell, Chemistry of Food. Compare rice. II Bell, Chemistry of Food. 171 172 ECONOMY OF FOOD Refuse. Water Pro- tein. Fat. • Carbo- hydrates. Fibre. Ash. Fuel Value per lb. Nutri- tive Ratio. Per Per Per Per Per Per Per cent. cent. cent. cent. cent. cent. cent. Kal. Legumes, t dry — Beans . — 13-6 231 2-3 63-6 3-9 3-6 1,523 1-2-54 Peas . . . — 14-3 22-6 1-7 53-2 6-6 2-7 1,480 1-2-62 Lentils . — 12-5 24-8 1-9 64-8 3-6 2-5 1,560 1-2-38 Nuts, in shell — Almonds . 46-0 2-7 11-6 30-2 9.5 M 1,660 1-6-78 Filberts . . 521 1-8 7-5 31-4 6-2 M 1,576 1-10-33 Peanuts 24-5 6-9 19-5 29-1 18-5 1-5 1,935 1-4-33 Cocoanuts % 48-8 7-2 2-9 25-9 14-3 0-9 1,413 1-25-20 Chestnuts . . 24-0 4-5 8-1 6-3 66.4 1-7 1,425 1-8-45 Wahiuts . . 74-1 0-6 7-2 14-6 3-0 — 0-5 805 1-6-02 „ kernels — 2-5 27-6 56-3 11-7 1-7 1-9 3,105 1-5-06 Brazil-nuts . 49-6 2-6 8-6 33-7 3-5 2-0 1,655 1-9-30 Fresh Vegetables— Turnips . . 30-0 62-7 0-9 0-1 5-7 1-3 0-6 125 1-6-58 Carrots . . 20-0 70-6 0-9 0-2 7-4 M 0-9 160 1-8-73 Beetroot . . 20-0 70-0 1-3 0-1 7-7 0-9 0-9 170 1-6-09 Parsnips 20-0 66-4 1-3 0-4 10-8 2-5 M 240 1-9-00 Radishes . 30-0 64-3 0-9 0-1 4-0 0-7 0-7 95 1-4-69 Potatoes . 20-0 62-6 1-8 0-1 14-7 0-4 0-8 310 1-8-29 Artichokes . — 79-6 2-6 0-2 16-7 0-8 1-0 365 1-6-59 Onions . 10-0 78-9 1-4 0-3 8-9 0-8 0-5 205 1-6-84 Leeks . . . 16-0 78-0 1-0 0-4 5-0 0-6 0-6 130 1-5-91 Cabbages . 15-0 77-7 1-4 0-2 4-8 M 0-9 125 1-3-76 Spinach — 92-3 2-1 0-3 3-2 0-9 21 110 1-1-88 Lettuces 15-0 80-5 1-0 0-2 2-5 0-7 0-8 75 1-2-95 Celery . . . 20-0 75-6 0-9 0-1 2-6 0-8 70 1-3-14 Cauliflower. . _ 92-3 1-8 0-5 4.7 1-0 0-7 140 1-3-24 Green peas. . 74-6 7-0 0-5 16-9 1-7 1-0 465 1-2-52 Butter beans . 50-0 29-4 4.7 0-3 14-6 1-0 370 1-3-25 Lima beans . 55-0 30-8 3-2 0-3 9-9 0-8 0-8 255 1-3-30 Tomatoes . — 94-3 0-9 0-4 3-9 0-6 0-6 105 1-5-34 Cucumbers 16-0 8M 0-7 0-2 2-6 0-7 0-4 170 1-4-36 Mushrooms — 88-1 3-6 0-4 6-8 0-8 1-2 210 1-2-20 * Including fibre, f Winter Blythe, Composition and Analysis of Food, X Including milk and shell. COMPOSITION AND RELATIVE VALUES 173 Refuse. Water. Pro- tein. Fat. .•Carbo- hydrates. Fibre. Ash. Fuel \ralue per lb. Nutri- tive Ratio. Fresh Fruits— Bananas . . Per cent. 35-0 Per cent. 48-9 Per cent. 0-8 Per cent. 0-4 Per cent. 14-3 Per cent. 1-0 Per cent 0-6 Kal. 300 1-1901 Apples . . . Pears . . . 25-0 10-0 63-3 76-0 0-3 0-5 0-3 0-4 10-8 12-7 1-2 2-7 0-3 0-4 220 260 1-38-27 1-27-21 Plums . . . Cherries . . 5-0 5-0 74-5 76-8 0-9 0-9 0-8 19-1 15-9 0-2 0-5 0-6 370 345 1-21-22 1-19-68 Apricots . . Peaches . . 6-0 18-0 79-9 73-3 1-0 0-6 0-1 12-6 7-7 3-6 0-5 0-3 255 155 1-12-60 1-16-85 Oranges . . Lemons. . . 27-0 30-0 63-4 62-5 0-6 0-7 0-1 0-5 8-5 5-9 M 0-4 0-4 170 145 1-14-54 1-10-05 Raspberries . Strawberries . 5-0 84-1 85-9 1-7 0-9 1-0 0-6 12-6 7-0 1-4 0-6 0-6 310 176 1-8-75 1-9-29 Watermelons . 59-4 37-5 0-2 0-1 2-7 — 0-1 60 1-14-63 Rhubarb . . 40-0 66-6 0-4 0-4 2-2 M 0-4 65 1-7-77 Dried Fruits— Figs. . . . Dates . . . Prunes . Raisins'. Currants . 10-0 15-0 10-0 18-8 13-8 19-0 13-1 17-2 4-3 1-9 1-8 2-3 2-4 0-3 2-5 3-0 1-7 74-2 70-6 62-2 68-5 74-2 — 2-4 1-2 2-0 3-1 4-5 1,475 1,450 1,190 1,445 1,495 1-17-41 1-40-14 1-34-55 1-32-74 1-32-52 Apples . . 5 Pears . . . — 28-1 16-5 1-6 2-8 22 5-4 66-1 72-9 3-7 2-0 2-4 1,350 1,636 1-44-43 1-30-41 Apple jelly . . Damson jam . . Marmalade . — 40-8 49-6 19-6 0-2 0-6 0-9 E 53-8 38-0 67-8 2-4 3-4 0*2 0-5 0-5 1,004 716 1,228 — Honey . . . — 17-4 0-1 0-4 81-9 — 0-2 1,525 — Including fibre. Appendix C CEREAL AND MILK PREPARATIONS : Carbo- 1 Ph i hydrates. * 1 1 aemarks. Per Per Per Per Per Per cent. cent. cent. cent. cent. cent. Allenbury's — No. 1 Milk food . 1-8 10-7 16-8 66-6 — 4-1 Made from milk. No. 2 Milk food . 2-2 10-2 14-9 68-8 3-8 '> >f >> No. 3 Malted Food 3-0 10-2 1-5 251 60-0 0-6 A partly malted wheat to be used with milk. Benger's Food . . 5-3 12-2 1-0 3-3 77-2 1-0 A malted wheat flour, peptonizes milk used in pre- paration. Cheltine'8— Milk food No. 1 . 5-2 9-6 9-8 71-2 " 4-2 42 per cent, lactose, no cane sugar or starch. Milk food No. 2 . 6-2 10-9 9-6 69-3 " 4-0 32 per cent, maltose, no cane sugar or starch. Malted Infants' food 3-6 14-6 43 35-4 40-5 1-6 A partly malted No. 3 cereal flour. Maltose food . . 5-8 7-4 0-6 83-4 — 2-8 Completely malted. Coomb's malted food , 6-0 10-6 0-9 81-7 0-8 Contains malt. Fairchild's milk pow- der Frame Food No. 1 . 5-5 1-2 — 92 — 1-2 Chiefly lactose. 2-1 12-4 82-9 2-6 Completely malted. ,, No. 2 . 1-4 16-3 — 30-3 50-1 1-9 Cooked wheat flour, plus sugar and Frame food extract 174 COMPOSITION AKD RELATIVE VALUES 175 Carbo- 1 .3 1 hydrates. i ^• Eemarks. ^ £ 02 Per Per Per Per Per Per cent. cent. cent. cent. cent. cent. Frame Food extract. 9-6 21-4 34-9 13-0 10-7 Made from wheat bran ; contains 3-7 per cent, phos- phoric acid. Horlick's malted milk 3-2 16-2 8-8 67-6 ~ 4-2 A dry powder made from wheat flour, malt and fresh milk Hovis Babies' Food No. 1 3-7 7-7 0-2 86-4 — 1-8 — „ „ ,, No. 2 2-4 5-8 0-1 82-4 7-5 1-7 — Maltico Food . . 2-5 16-0 11-7 — 66-2 3-6 Malted cereals and milk. Mellin's Food . . 3-5 9-1 0-1 83-7 " 3-3 A completely malted cereal extract, to be used with milk. Muffler's Food . . 5-6 14-3 5-8 27-4 44-4 2-4 Desiccated milk, white of egg, wheat flour and lactose. Neaves' Milk Food . 2-4 20-0 26-0 47-1 4-5 Diluted with 7 to 8 parts of water, the mixture resembles human milk. Infants' Food 5-1 14-7 — 75 •5 1-2 A cereal flour to be used with milk. Opmus Food 10-9 9-1 1-0 78 •6 0-4 A granulated wheat flour. Ridge's Food 4-3 9-4 1-6 83 •7 0-9 A cooked cereal flour. Savory & Moore's 5-3 10-8 M 27-8 54-1 0-9 Wheat flour, malt, Food glucose and cane sugar. Appendix D MEAT PREPARATIONS* Protein Nitro- Nitrogen Water. and Extrac- tives Free Ash. Gelatin. Substance. Per Per Per Per Per cent. cent. cent. cent. cent. Meat Juice— Armour's Beef Juice . 74-4 8-1 9-5 7-5 Bovril 62-0 7-2 14-0 20-7 5-9 Brand's „ „ . 60-7 6-1 10-1 1-3 10-0 Valentine's „ „ 60-3 0-6 29-2 11-3 Weyth's 44-9 380 — — 171 Meat Extracts— Armour's Extract of Beef 24-3 16-1 20-5 20-1 19-0 Bovril 21-2 16-7 16-1 29-2 16-8 Invalid's Bovril. 21-5 31-4 32-6 16-2 Bouillon Fleet . . . 62-0 11-8 9-9 3-9 12-5 Brand's Essence of Beef 89-2 6-7 4.4 0-1 1-4 Liebig's Extract (Lemco) 19-3 49-8 10-7 — 20-2 0x0 41-6 36-0 4-5 18-0 Home-made beef tea . 96-0 1-5 0-6 1-0 0-7 COMMERCIAL PEPTONES Water Peptones. Albu- moaes. Extrac- tives, etc. Ash. Armour's Wine of Peptone Benger's Peptonized Beef Jelly Camrick's Liquid Pepton- oids Fairchild's Panopeptone . Per cent. 83-0 89-7 80-1 810 Per cent. 4-7 4-6 Per cent. •0 2-4 2-3 Per cent. 12-9 2-3 12-Ot 150t Per cent. 11 0-9 1-0 ♦ Variable. f Soluble carbohydrates. 17« Appendix E MILK PREPARATIONS AND MISCELLANEOUS PRODUCTS Water. Pro- tein. Fat. Carbo- hydrates. Ash. Remarks. Per Per Per Per Per cent. cent. cent. cent. cent. Condensed milk — Unsweetened . 69-2 8-7 8-1 9-9 1-6 Condensed 2*2 times. Sweetened . 25-7 8-5 10-6 53-8 1-3 Condensed 2*3 times and 42 per cent. ca,ne sugar added. „ skimmed 30-7 12-2 3-1 52-1 2-1 Desiccated milk . . 27-5 28-3 38-6 5-5 Calculated. Lacvitum 5-3 28-0 29-4 31-3 6-0 Plasmon .... 8-5 75-0 0-2 8-9 7-4 Biogene .... 10-0 78-7 1-6 4-0 4-7 — Casumen .... 7-0 86-5 3-6 — 2-9 — Gelatin .... 13-6 91-4* 0-1 21 Fuel value 1705 kal. Isinglass .... 19-0 89-3t 1-6 — 2-0 „ » 1730 „ Calvesfoot jelly . 77-6 4-3 — 17-4 0-7 ,. » 405 „ Desiccated eggs . 5M 39-9 _ 9-0 Calculated. t 5-9 48-1 40-5 — 5-3 As sold. Egg substitute 7-0 18-7 3-4 70 •9 §Custard powder (a) . 13-7 0-6 — 84-5 0-4 — » (&) . 8-2 5-0 53-9 26-7 Ash, baking soda; 6 per cent, tar- taric acid. ♦ Too high ; by difference 84-2. X Leach, Food Inspection. t Too high; by difference 77-4. § Food and Sanitation, 1893. Appendix F THE RELATIVE VALUE OF FOODS Number Value compared with Average Market Price Food. of Units.* tBeef Milk Bread Beef at as 100. as 100. as 100. Sd.perlb. per lb. Rel. val. Rel. val. Eel. val. Pence. Pence. Bee/— Leg, including bone . 213-2 52 239 88 ^L 5 „ edible matter . 461-6 107 517 191 8i 7-8 Round .... 431-2 100 483 178 8 9-lOi H bone . 3820 89 428 157 ^l 6-7 Rump 356-8 83 400 147 H 11-14 Thick flank 416-0 96 466 172 n 9-10 Thin flank 405-2 94 454 167 n 5-6 Loin . . 392 91 439 161 u 11-12 Ribs . . 362-8 84 406 150 t6i 9-11 Brisket . 3292 76 369 136 6 7 Neck . . 3352 78 375 138 m 5 Side, very lean 350-8 81 393 144 H — „ lean . 352-4 82 395 145 6f — „ med. fat 368-4 85 413 152 6| — „ very fat 406-4 94 455 168 7i — Ox tails . . 3880 90 434 160 t7i — Ox tongues . 308-8 72 345 127 a — Kidneys . 281-6 65 315 113 5i 12 Sweetbreads . 384-4 89 430 158 !t — Tripe . . . 238-8 55 266 99 H 6 Suet . . . 327-2 76 366 135 6 8 Veal— Hock . . . 160-8 37 180 66 ^^ 6 FiUet . . . 341-6 79 383 146 6i 13 Loin, whole . 368-0 85 412 151 6i 9-10 Breast 356-0 83 399 147 H H Neck, best end 340-8 79 382 140 6i 10-12 Shoulder . 353-6 82 395 146 m 8 Fore knuckle. 256-4 59 287 106 J4| 6 Scrag .... 296-4 68 332 122 JSi 6 * This column may be road t Roxmd. ' Value compared with sugar as 100.' J Add allowance for bone. 178 COMPOSITION AND RELATIVE VALUES 179 Number of Units.* Value compared with Average Food. tBeef Milk Bread Beef at Market Price as 100. as 100. as 100. Srf.perlb per lb. Rel. val. Rel. val. Rel. val. Pence. Pence. Mutton— Leg 360-8 84 403 149 6J 10 Loinf 383-2 89 429 158 7 12 Neck, best end . . 344-8 80 385 142 §6^ 10 Breast .... 423-6 98 474 175 n 4 Scrag 317-6 74 356 131 §6 6-7 Shoulder .... 336-0 78 376 139 §6i 8-9 Kidneys .... 342-8 79 384 141 6i 12 Heart . . . . . 388-4 90 435 160 n 6 Lungs .... 415-2 96 465 171 n 4 Liver 503-0 114 563 208 9 5 Suet 3816 88 427 157 7 5 Lamb — Leg 372 4 86 417 154 7 12 Loin 416-4 96 466 172 7| 11 Shoulder .... 382-4 89 428 157 7 11 Breast .... 384-4 89 430 159 7 7 Neck 373-6 87 417 154 7 H Pork, fresh- Leg 373-6 87 417 154 7 9 Hind loin. 364-8 85 409 151 6f 10^ Fore loin .... 384-0 89 430 158 7 8i Hand 359-2 83 402 148 6| 7 Belly 356-4 83 399 147 H 8| Lard II 4000 93 448 165 7|- 7 Bacon, smoked, lean . 402 93 450 166 n 16-12 » „ fat 430-8 100 481 178 8 Poultry— Chickens .... 261-6 61 293 108 5 12-15 Fowls 3232 75 362 133 6 10-12 Turkeys .... 395-6 92 443 163 n 12 Geese 387-2 90 434 160 7 8 Fish, fresh, whole- Haddock If . . . 168-8 39 189 70 3 6 Cod 168-8 39 189 70 3 4 Hake If . . . . 147-2 34 165 61 2f 4 Flounder .... 109-2 25 122 46 2^ 4 ♦ This column may be read " Value compared with sugar as 100." t Round. % Without kidney and suet. § Add allowance for bono. II Vegetable oils and all pure fats, same as lard except in regard to price. T[ EntraUa removed. 180 ECONOMY OF FOOD Food. Fishy fresh {conid.) Herring . . Mackerel . Turbot . . Salmon . Cod steaks . Halibut steaks Skate, lobe . Fish, cured — Cod, salted . Haddock, smoked fillet . . Herring, smoked. Dairy Produce — Milk (cow's), whole ,y „ skim Cream, thick „ thin . Butter II . . . Cheese, Cheddar „ Dutch . Eggs (hen's) . . Cereals and Farinaceous Products — Wheat flour, white Bread, white Macaroni Barley, pearl Rice . Cornflour . Oatmeal . Tapioca . Arrowroot Legumes — Beans Peas . Lentils Number of Unita.* 239-6 220-8 184-0 341-6 342-0 323-6 180-8 381-6 316-4 466-8 445-2 89-3 74-3 174-3 63-8 360-0 705-3 426-3 299-2 302-9 242-3 345-7 252-2 240-2 126-6 416-5 96-4 97-5 524-8 5120 5584 Value compared with fBeef as 100. Rel. val. 56 51 43 79 79 75 42 88 73 108 103 21 17 40 15 83 164 99 70 56 80 68 56 29 97 22 23 122 119 129 Milk as 100. Rel. val. 268 247 206 382 383 362 202 427 354 523 498 100 83 195 71 403 790 477 332 339 271 387 282 270 143 466 108 109 587 573 654 Bread as 100. Beef at 8d. per lb. Rel. val. 99 91 76 141 142 134 75 158 131 193 184 37 31 72 26 149 291 176 123 125 100 143 104 99 52 172 40 40 233 211 230 Average Market Price per lb. Pence. ^ 4 6 4 7 5| 8| 8 m §4 tn 6J 13 8 Bread at lidperlb, If n 2 H H f H 3 H * This column may be read " Value compared with sugar as 100. t Roxmd. X ^^^ quart. § Per pint. II Margarine same_a8 butter except price. ^ Per dozen. COMPOSITION AND RELATIVE VALUES 181 Number Value compared with Average Food. nf Market OI Units.* tBeef Milk Bread Bread at Price as 100. as 100. as 100. lirf.perlb. per lb. Rel. val. Rel. val. Rel. val. Pence. Pence. Nuts— Walnuts .... 2054 48 230 85 li 6 Chestnuts . . . 239-6 56 268 99 l| 3 Peanuts .... 6249 121 588 217 3i 6 Fresh Vegetahlea— Potatoes .... 611 12 67 21 i \ Onions .... 38-1 9 43 16 1 if Leeks .... 26-6 6 30 11 + Turnips .... 241 6 27 10 :; Carrots .... 26-2 6 29 11 '. '. Cabbage .... 33-6 8 38 14 X Green Peas . . . 168-9 37 178 66 1 Tomatoes . . . 235 5 26 10 { Fresh Fruits— Bananas .... 31-9 7 36 13 X Apples .... 18-0 4 20 7 X Plums . . 37-1 9 42 15 X Oranges .... 20-9 5 23 9 + Dried Fruits— Figs 161-4 37 181 67 1 3 Dates .... 118-6 26 132 49 i 2 Prunes .... 98-2 23 110 41 i 4 Raisins » . . . 126-5 29 142 62 i 3i-7i Currants .... 1290 30 144 53 I 3I4 Miscellaneous— Sugar .... 1000 23 112 41 2 Treacle .... 26-0 60 29 107 H 2i-3 Damson jam . 48-0 11 54 19 1 4-6 Honey .... 85-5 19 95 35 7-11 ♦ This column may be read t Roimd. j Less than a farthing. Value compared with sugar as 100.' 182 ECONOMY OF FOOD O M M P P-l i I I I I I 1 D B i M I I M I M IOCDOOO>-ICO'*COOO f-( (M (N (N (M (N CQpOCt>t-I>l>00 .^ I I I I I I I I I I $S.-i(MeOT*05p00050 ogeouscoooOT'cC'^cOQp -^ I « I M i I M I g£ ocq5pM-^»pi>op fti-H f-H (N N C^ ^ N N .^ I I i i I I I i g,gi-Hoo eo CO I I gr;©